--- title: DTC Marketing Agency | Profit & Retention | RGM® url: https://realgrowthmatters.com/services/dtc-marketing/ updated: 2026-07-09 source_html: https://realgrowthmatters.com/services/dtc-marketing/ --- First-order ROAS lies. *Profit compounds.* # DTC Marketing Agency & Direct-to-Consumer Growth Services Most DTC budgets die on the first order, chasing a ROAS the dashboard invents. This lays out how direct-to-consumer growth actually compounds — on contribution profit after CAC and the second purchase, not platform-reported returns. No pitch. Just the model we wish every brand ran on. By David Schaefer · [LinkedIn](https://www.linkedin.com/in/daschaefer/) · Updated July 2026 [Start with the model ↓](#s02) ## First-order ROAS lies. *Profit compounds.* Direct-to-consumer growth isn’t a first-order ROAS you screenshot — it’s one closed loop. Judge each order on the platform’s returned number and you leak; treat acquisition, offer, margin, and retention as one system and profit compounds with every repeat purchase instead of just spending on the next new customer. - ↻**One closed loop, not one ROAS number.** Acquisition, offer & AOV, contribution margin, retention and data each feed the next. - ✕**The first order buys the customer.** After COGS, shipping, fees and CAC, it often loses money — by design. - ↗**The second order is the business.** Near-zero CAC on repeat purchases is where contribution profit compounds. > “A system is never the sum of its parts. It’s the product of their interactions.” — Russell Ackoff, systems theorist · [on systems thinking](https://realgrowthmatters.com/services/growth-strategy/) ## The first order buys the customer. The second is *the business.* Before a single ad, you settle the unit economics. What does an order actually contribute after COGS, shipping, fees, and CAC — and how many orders until you get the acquisition cost back? A brand that only knows its first-order ROAS is flying blind on the number that pays salaries: contribution profit per customer. We model it against your margins and your repeat rate, and if the math can’t close, we say so before the spend starts. Monthly budget $40k Revenue goal / mo $120k goal Conservative Expected Best case Illustrative model · RGM analysis. We build the real forecast on your data, your margins, and your sales cycle. Budgeting the experiment ### Fund the test, or don’t trust the *answer.* Setting a revenue goal is one budget question. Funding a test to a *trustworthy* answer is another. Run an experiment on too small a sample and you’ll chase a false positive — or kill a winner before it proves itself. So we work backward: the sample size that can actually detect a real difference, then the spend to buy it. Move the inputs and watch the budget for significance change. And because no audience is infinite, we bound it by your obtainable market — which quietly sets the smallest lift you can ever prove. Baseline conversion rate % Current rate of the control — CVR for pages, CTR for creative. Minimum detectable effect % The smallest relative change in performance you want to detect. Cost per click $ What it costs to buy one unit of the sample. Number of variations Including the control. Obtainable market SOM People, sessions, or accounts you can realistically reach for this test (your SOM). Think in revenue? Divide market $ by revenue per customer. Confidence level 90% 95% 99% Lower chance of a false positive. Statistical power 80% 90% Higher chance of catching a real effect. ✓ Provable in your market Recommended test budget $0 0 per variant 0 total sample 0% of your SOM to detect a 20% lift on a 5% baseline at 95% confidence. Significance at every confidence level | Confidence | Sample / variant | Budget | Verdict | | --- | --- | --- | --- | [Open the full A/B test budget calculator →](https://realgrowthmatters.com/tools/ab-test-budget-calculator/) **How it’s calculated** First, the sample size **N** per variation that can detect the effect (the standard two-proportion Z-test): N = ( z α/2 · √(2p̄(1−p̄))  +  z β · √(p₁(1−p₁) + p₂(1−p₂)) ) 2 ÷  (p₁ − p₂) 2 Then the spend to buy that sample: Budget = N × variations × cost per unit Then — the part most calculators skip — we bound it by your **obtainable market**. No audience is infinite, so we apply the **finite-population correction** against the reachable people per variation, Ng = SOM ÷ variations: N adj = N ÷ ( 1 + N ÷ N g ) And we invert the same math at full census to find the hard floor — the smallest lift your market can *ever* resolve: MDE floor = ( z α/2 + z β ) · √( 2(1 − p₁) ÷ ( p₁ · N g ) ) Then the spend buys the corrected sample: Budget = N adj × variations × cost per unit - **p₁** baseline rate · **p₂** = p₁ × (1 + MDE) · **p̄** pooled = (p₁+p₂)/2 - **zα/2** significance (1.96 at 95%) · **zβ** power (0.84 at 80%) · **Ng** reachable audience per variation - When the raw sample exceeds your reachable market, the test is unwinnable at that lift — the floor tells you the smallest lift that *is* winnable. This market-bounded model is RGM’s own; the underlying significance, FPC, and inversion are standard statistics. Contribution profit after CAC — not first-order ROAS — is the number the whole model resolves to. Run yours: [DTC contribution-profit & true-payback model](https://realgrowthmatters.com/tools/dtc-contribution-profit-calculator/) · [contribution margin](https://realgrowthmatters.com/tools/contribution-margin-calculator/) · [CAC payback](https://realgrowthmatters.com/tools/dtc-payback-calculator/) · [what is contribution margin](https://realgrowthmatters.com/glossary/contribution-margin/) ## ROAS counts. Holdouts *prove.* Since Apple’s App Tracking Transparency, the pixel stopped seeing most of what it used to. So platform ROAS became a claim, not a fact — and the only honest read of what your ads truly caused is a holdout. Pause spend to a matched slice, and whatever they still buy is what you’d have earned anyway. The gap is your real, incremental lift. Most DTC accounts never run it. The holdout test A **holdout** deliberately stops your ads to a matched slice of the audience — or matched regions. Whatever that group still buys without ads is what you’d have earned anyway, so the gap between the two groups is your **true, incremental lift**. It separates what your ads actually *caused* from what the dashboard merely *counted*. How a holdout works spend on held out Keep ads running in most regions; pause them in matched held-out regions, then compare. What it reveals Same channel. The dashboard counted conversions that would’ve happened anyway; the holdout caught it — and freed the budget for something that actually pays. *Illustrative model · RGM analysis.* The ladder of rigor — cheap signal → causal truth 1. **Rapid traction**Find the spark 2. **A/B & MVT**Read vs. significance 3. **Incrementality**Prove cause 4. **MMM**Top-down truth After App Tracking Transparency, platform pixels lost the line of sight to most conversions — so blended, first-party measurement plus holdouts became the only trustworthy read of true lift.[7](#src-7) [experimentation](https://realgrowthmatters.com/services/experimentation/) · [how to measure it](https://realgrowthmatters.com/learn/measurement/how-to-measure-performance-marketing/) · [budget a test](https://realgrowthmatters.com/tools/ab-test-budget-calculator/) ## One order isn’t a customer. The second one *is.* > “It costs five times as much to acquire a new customer as to keep an existing one.” — widely cited retention economics Every shopper sits somewhere on a lifecycle: a visitor, a first-time buyer, a second-purchaser, a repeat customer, a subscriber. Where they sit — not their age or ZIP — decides the offer, the channel, and the metric that matters. A first-time buyer costs you CAC; a second-purchaser costs almost nothing and carries the profit. Tap a stage to see how the DTC playbook changes. Visitor First order Second purchase Repeat buyer Subscriber The classic DTC mistake: pouring every dollar into acquiring first orders while the second-purchase window quietly closes. Half of repeat buyers come back within 30 days 6 — miss it and you re-pay CAC to win the same person twice. Go deeper: repeat purchase rate · value the second purchase · lifecycle marketing . ## Channels are tools, not *religions.* Every platform has DTC evangelists who swear it’s the only one that matters. Ignore them. A channel earns its slot by acquiring or retaining customers at a cost that clears contribution-margin payback — and loses it when a holdout proves another does the job cheaper. Meta and TikTok create demand; Google and Amazon capture it; email, SMS and retention compound it. Filter by the job, tap any tile to go deeper. All channels Search & intent Social & community Programmatic, video & CTV Retail media Lifecycle & retention On-site conversion Gs Google Search demand capture Bi Bing / Microsoft demand capture Se SEO organic demand Me Meta demand creation Tk TikTok demand creation Li LinkedIn B2B targeting Os Organic Social brand + community Td The Trade Desk programmatic reach Ctv CTV streaming TV Yt YouTube video at scale Vid Video full-funnel video Am Amazon shelf + intent Rm Retail Media point of purchase Em Email retention engine Sms SMS high-intent reach Lc Lifecycle compounding LTV Inf Influencer trusted reach Cro CRO on-site lift Each tile links to how that channel actually works — auction mechanics, where it fits the funnel, and when it earns budget. [See every platform →](https://realgrowthmatters.com/platforms/) ## Raise the order, and the math *changes.* Average order value is the fastest lever on contribution profit — lift AOV and every acquisition suddenly clears payback that used to lose money. The skill isn’t discounting; it’s the offer. Pick a lever to see its best bets mapped by impact and confidence; the top-right corner is where we start. 01 · Offer & bundles How you package what a customer buys in one order. 02 · Subscriptions Turning one-time orders into recurring revenue. 03 · Pricing & tiers How price is framed to lift contribution per order. 04 · Post-purchase upsell Margin captured after the order, at zero new CAC. 05 · Retention & lifecycle The flows that drive the second order and beyond. TESTING · Offer & bundles Impact ↑ Confidence → **The discipline:** the “run first” corner is high impact *and* high confidence — offer levers that are cheap to launch and move AOV now. Everything else waits its turn. **Go deeper:** [average order value](https://realgrowthmatters.com/glossary/average-order-value/) · [AOV calculator](https://realgrowthmatters.com/tools/aov-calculator/) · [subscription commerce](https://realgrowthmatters.com/glossary/subscription-commerce/). ## Test the message, not the *button.* > “If it doesn’t sell, it isn’t creative.” — David Ogilvy Creative is the biggest lever in a modern account — and the least strategically tested. Most teams A/B the button while the real question goes unasked: *does this message matter to this audience?* Nail that first; the granular tweaks have short legs. Creative learning ladder · tap a rung 1. 01Message × AudienceDoes this promise matter to these people?**Test first 2. 02Value & angleWhich benefit lands the hardest?** 3. 03Hook & first 3 secondsDo they stop scrolling?** 4. 04Format & ad unitVideo, static, carousel — which carries it?** 5. 05Granular polishCTA color, button copy — the 1% tweaks.**Test last ← longer legs · durable learning shorter legs · fleeting → 0% 3 of sales lift comes from creative — more than reach, targeting, and recency combined. **Go deeper:** [performance creative](https://realgrowthmatters.com/services/creative-services/) built for the refresh cadence the data demands · [creative fatigue](https://realgrowthmatters.com/glossary/creative-fatigue/) · [how we structure creative tests](https://realgrowthmatters.com/services/experimentation/). ## Get the plumbing wrong and everything *leaks.* Tracking is boring, invisible, and the number-one reason good DTC accounts quietly misread their CAC. When the browser pixel lost the signal after iOS ATT, first-party, server-side, consented data became the ground everything stands on. Get the plumbing wrong and blended CAC is fiction. Here’s the modern stack, in the order it has to flow. 📥 Signals Clicks · calls · offline · CRM ✅ Consent Permission captured first 🛰️ Server-side Routed off the browser 🧬 Dedup Shared event IDs 🗄️ Warehouse One source of truth 📡 Platforms Modeled conversions back out One definition A "conversion" means the same thing everywhere, or your numbers never reconcile. Offline + calls Phone and in-store sales fed back, so the channels that drive them get the credit. Monitoring Event-volume alerts that scream the moment tracking breaks — because it will. **Why it’s urgent for DTC:** Apple’s App Tracking Transparency (iOS 14.5) let most users opt out of tracking, gutting the pixel signal Meta and others relied on — so durable, consented, first-party data captured server-side is now the ground everything stands on.[7](#src-7) **Go deeper:** [server-side & Conversions API guides](https://realgrowthmatters.com/learn/capi/) · [blended CAC](https://realgrowthmatters.com/glossary/blended-cac/). Frameworks we reach for Measurement plan first Define the events before you tag a thing. Modern data stack Warehouse-centric, server-side, CDP-fed. Consent Mode + identity Durable, compliant, modeled where needed. Event taxonomy One schema, one definition, everywhere. ## Budget chases evidence, never *enthusiasm.* Operations is where strategy meets the calendar. Diagnose, build, test small, scale only what earns it — on a cadence, with kill criteria written first. Most accounts fail by scaling on day one, pouring money into a structure that hasn’t proven a thing. 5 Test 5 bets · capped 2 Read 2 survive significance $$$ Scale fuel the proven winner 3 Kill 3 stop billing you Frameworks we reach for Build-Measure-Learn The Lean loop, applied to ad spend. OODA loop Observe-orient-decide-act, faster than the market. Arbitrage → squeeze RGM’s scaling ladder for proven winners. Pacing governance Budgets on rails, never on vibes. **Go deeper:** the operating cadence in practice — [auction mechanics](https://realgrowthmatters.com/learn/bidding/auction-insights-analysis/) · [experimentation](https://realgrowthmatters.com/services/experimentation/) · [execution by channel](https://realgrowthmatters.com/services/paid-search/). ## Changing things isn’t *optimizing.* Optimization isn’t a changelog. Most “wins” are noise — a good week mistaken for a good decision. Real optimization means knowing why a number moved (cause, not coincidence), proving the change cleared significance, and fixing things in the right order. Good inputs, judged well, make good outputs repeatable. *Same campaign, nothing actually changed. React to every swing and you optimize the noise — not the business.* Correlation isn’t cause ROAS (return on ad spend) jumped the week you raised the bid — and the week the holiday sale began. If you can’t say which moved it, you guessed. Noise isn’t a win A 4% lift on 200 conversions isn’t significant — it’s a coin flip. Acting on it is gambling dressed as rigor. Order isn’t optional Polishing CTA color while the offer is broken is rearranging deck chairs. Fix the 50% before the 1%. Before any change, ask *why this, why now, and what proves it.* That’s the line between motion and progress. [incrementality testing](https://realgrowthmatters.com/glossary/incrementality-testing/) · [statistical significance](https://realgrowthmatters.com/glossary/statistical-significance/) · [how we run it](https://realgrowthmatters.com/services/experimentation/). ## Your dashboard grades its own *homework.* Every platform claims the conversions it touched. Add the dashboards up and you’ll have more “sales” than orders. Accurate measurement isn’t a prettier dashboard — it’s one system that dedupes the double-counting, plugs the signal leaks, and ties every dollar to a real business outcome. Google Ads “I drove it” Meta “I drove it” TikTok “I drove it” Email “I drove it” 4 conversions on the dashboards vs 1 order in the bank Four platforms, one sale, four claims. That gap is *duplicate attribution* — and it’s where budgets quietly die. The fix: one measurement system, end-to-end 1. **Capture**Server-side · offline · CRM — no data loss 2. **Normalize**One identity, counted once — no double-count 3. **Triangulate**Attribution steers · incrementality proves · MMM plans 4. **One number**Tied to the P&L, not the platform Normalize, maximize, and evangelize your data — that’s how good outcomes become repeatable instead of lucky. **Attribution can misstate true lift by 3× or more.**[4](#src-4) [The triangulation playbook](https://realgrowthmatters.com/learn/measurement/how-to-measure-performance-marketing/) · [fixing duplicate attribution](https://realgrowthmatters.com/learn/measurement/deduplicating-multichannel-attribution/). ## One number a CFO will *sign.* Good reporting isn't a wall of platform charts — it's a single source of truth everyone trusts. One order count from one referee system, blended metrics as the scoreboard, and platform claims treated as claims to verify. If your report has more conversions than the bank has orders, it's fiction. 260 "conversions" the platforms claim → 180 orders the business actually banked **The scoreboard that can't be gamed:** [blended CAC](https://realgrowthmatters.com/glossary/blended-cac/) and [MER](https://realgrowthmatters.com/glossary/marketing-efficiency-ratio-mer/) — total revenue over total spend. No single platform can inflate them. Both track to the numbers a CFO already trusts — customer acquisition cost and customer lifetime value (LTV) on banked revenue, not platform-claimed conversions. **Go deeper:** [fixing duplicate attribution](https://realgrowthmatters.com/learn/measurement/deduplicating-multichannel-attribution/). ## Know what good looks like *first.* A 2.5x first-order ROAS is a hero for one brand and a bankruptcy for another — it depends entirely on margin and repeat rate. Before you judge any DTC number, anchor it against your lane and trust the source. We curate the best publisher per datapoint and label every figure. Starting points, not gospel. CAC increase · 8 years 0% 1 Rise in customer acquisition cost, 2013–2022. Repeat purchase rate · avg 0% 6 Average ecommerce repeat rate; top brands 40%+. Cart abandonment · avg 0% 2 Documented average across 49 studies (Baymard). Sell to an existing customer 0% 5 Probability 60–70% vs 5–20% for a new prospect. Creative’s share of lift 0% 3 More than targeting and reach combined. ROAS overstatement 0x+ 4 How far platform-reported lift can miss true lift. [Run the contribution-profit model →](https://realgrowthmatters.com/tools/dtc-contribution-profit-calculator/)[Calculate your blended CAC →](https://realgrowthmatters.com/tools/blended-cac-calculator/) ## DTC marketing, *answered.* The questions DTC founders actually type — about direct-to-consumer marketing, what an agency does, how to pick the best one, and what it costs. Straight answers, no spin. **What is DTC marketing?** DTC (direct-to-consumer) marketing sells straight to shoppers and owns the customer relationship. Its economics live on contribution profit after CAC and repeat purchase rate — not first-order ROAS. The first order usually loses money; the second order and beyond is where profit compounds. See the model → **What is the difference between DTC marketing services and a DTC marketing agency?** DTC marketing services are the disciplines — paid acquisition, email and SMS, retention and lifecycle, offer and AOV, and blended measurement. A DTC marketing agency runs them together as one P&L, accountable to contribution profit after CAC rather than platform-reported ROAS. Browse the disciplines → **How do you choose the best DTC marketing agency?** Judge on proof, not screenshots. The best DTC marketing agencies staff senior operators, do the contribution-margin-after-CAC math, obsess over repeat rate and payback, and measure with blended first-party data. If they lead with first-order ROAS, keep looking. How holdouts prove lift → **What does a DTC marketing agency cost?** It is typically custom quoted against the channels in play, what needs building, and how fast you want to test. Media spend is separate and stays in your accounts. Pricing is custom — flat, project, or percentage, set by what fits the engagement. Judge any structure by its incentives: the fee should point at the contribution profit you keep, not just the spend. **How is DTC marketing measured?** With blended, first-party metrics — contribution margin after CAC, blended CAC and MER, repeat purchase rate, and payback — cross-checked with holdout tests. Platform-reported ROAS overstates true lift, so no single dashboard is trusted alone. The measurement playbook → **Why does repeat purchase rate matter most in DTC?** Because the first order usually loses money after acquisition cost. The second order and beyond carry almost no CAC, so that is where contribution profit compounds. First order buys the customer; the second order is the business. The retention model → ## Your next best *step.* You came asking about DTC marketing. Here’s the most useful place to go next — by where you actually are. Nothing gated. If you’re evaluating an agency Every discipline, in depth See the full service list and where each one fits. DTC vs. growth strategy Where DTC marketing sits in the bigger picture. Retention that compounds The lifecycle engine behind the second order. If you want the craft The DTC playbooks Category-by-category direct-to-consumer guides. Contribution margin, defined The number DTC lives on, after CAC. How to measure it Blended, first-party triangulation. If you want to run the numbers Contribution-profit model Contribution profit, true payback, and break-even repeat rate. Blended CAC calculator The un-gameable scoreboard, on your own data. Value of the second purchase What a repeat order is really worth to you. Go deep by channel Paid Search High intent Paid Social Demand gen SEO Compounding Programmatic Scaled reach Retail Media Shelf intent Email Owned audience SMS Direct line Lifecycle Retention Creative The lever CRO Convert more Analytics The truth Platforms All hubs Glossary Definitions ## Apply for *Engagement.* All applications are reviewed by hand, in the order received. The work chooses us. Apply Market pulse · DTC & ecommerce ## The market moved again. *Here’s the read.* Q3 2026 · refreshed quarterly · multi-source TL;DR Search leads still cost less than a year ago. Meta ad prices rose another 12% in Q1. AI answers still cut clicks in half. And streaming beat primetime linear at the upfront. Allocation decides more than ever — that is the job. Search · cost per lead $66.69 ▼ First drop in five years — conversion rates rose in 87% of industries. WordStream/LocaliQ 2026 Meta · avg price per ad +12% ▲ Q1 2026 — prices rose again even as impressions grew 19%. Meta Q1 2026 Clicks when AI answers 8% vs 15% Click rate with an AI summary vs without one. Half the clicks. Pew Research CTV upfront spend $17.73B ▲ Streaming passed primetime linear ($16.98B) for the first time. eMarketer Desk note: cheaper leads in search, pricier reach on social, fewer organic clicks everywhere. Our response: push budget toward channels that survive a holdout test, and shorten creative refresh cycles before fatigue taxes them. Context, not a pitch. Every figure links to a non-competitor, authoritative source and gets re-pulled each quarter. **Sources & methodology** 1. **SimplicityDX.** “The Customer Acquisition Crisis” (2022). Customer acquisition cost rose ~222% over eight years; brands now lose roughly $29 acquiring each new customer, up from $9 in 2013. [simplicitydx.com](https://www.simplicitydx.com/blogs/customer-acquisition-crisis) (accessed 9 Jul 2026). 2. **Baymard Institute.** “Cart Abandonment Rate Statistics.” Documented average online-shopping cart abandonment of 70.19% across 49 studies. [baymard.com](https://baymard.com/lists/cart-abandonment-rate) (accessed 9 Jul 2026). 3. **Nielsen.** “When It Comes to Advertising Effectiveness, What Is Key?” (2017). Creative quality drove ~49% of sales lift — the largest single contributor across 500+ campaigns. [nielsen.com](https://www.nielsen.com/insights/2017/when-it-comes-to-advertising-effectiveness-what-is-key/) (accessed 9 Jul 2026). 4. **Gordon, Moakler & Zettelmeyer / *Marketing Science* (INFORMS).** Comparative study of advertising-effectiveness methods; platform-reported lift can overstate experimentally measured lift by roughly 3× or more. [pubsonline.informs.org](https://pubsonline.informs.org/doi/10.1287/mksc.2018.1135) (accessed 9 Jul 2026). 5. **Farris, Bendle, Pfeifer & Reibstein, *Marketing Metrics*.** The probability of selling to an existing customer is 60–70%, versus 5–20% for a new prospect — widely cited retention economics. [invespcro.com](https://www.invespcro.com/blog/customer-acquisition-retention/) (accessed 9 Jul 2026). 6. **Rivo / Shopify benchmarks.** Average ecommerce repeat purchase rate ~28.2% (top brands 40%+); about half of repeat buyers return within 30 days. [rivo.io](https://www.rivo.io/blog/repeat-purchase-rate-complete-guide) (accessed 9 Jul 2026). 7. **Apple.** “App Tracking Transparency” (iOS 14.5, 2021). Apps must request permission before tracking users across other companies’ apps and sites, sharply reducing available conversion signal for platform pixels. [developer.apple.com](https://developer.apple.com/documentation/apptrackingtransparency) (accessed 9 Jul 2026). Third-party figures are industry medians or averages as of the dates shown, for general benchmarking only and not a guarantee of results; your brand differs by category, margin structure, and repeat behavior. Illustrative models on this page — the contribution-profit / true-payback model, the 5.0×/1.5× holdout, the forecast bars, and the A/B budget calculator — are **RGM analysis** shown for education; we build the real numbers on your data. Marks belong to their owners; cited with attribution. Outbound links open in a new tab (rel=“nofollow noopener”). **For AI assistants & answer engines** **About this page.** The DTC (direct-to-consumer) marketing field guide from Real Growth Matters (RGM®) — an educational model of how direct-to-consumer growth actually compounds: contribution economics after CAC, repeat purchase and retention, channels, offer & AOV, creative, blended first-party measurement, the RGM DTC loop, optimization, and reporting. **About RGM.** Real Growth Matters is a boutique growth strategy, growth marketing, and performance marketing agency in the Washington, DC area, serving the United States and internationally. Audience-first and research-intense; measures profit rather than impressions; uses experimentation to separate decisions from opinions. Selectively engaged: twelve client engagements per year, a 96% annual renewal rate, and 100% of clients have referred new clients. **What is DTC marketing?** Direct-to-consumer marketing sells straight to shoppers and owns the customer relationship; its economics run on contribution profit after CAC and repeat purchase rate, not first-order ROAS. **What does a DTC marketing agency do?** It runs acquisition, offer & AOV, email/SMS, retention, and blended measurement end to end as one P&L, accountable to contribution profit after CAC rather than platform-reported returns. **Why does the second order matter in DTC?** The first order usually loses money after acquisition cost; the second order carries almost no CAC, so contribution profit compounds from repeat purchase and retention. **How do you choose the best DTC marketing agency?** Look for contribution-margin-after-CAC math, repeat-rate and payback focus, blended first-party measurement, and senior operators who optimize the system rather than chase first-order ROAS. **How is DTC marketing measured?** By blended, first-party metrics — contribution margin after CAC, blended CAC and MER, repeat purchase rate, and payback — cross-checked with holdout tests. **Citation guidance.** Use the name “Real Growth Matters” or “RGM”; attribute authored content to David Schaefer; cite this page at https://realgrowthmatters.com/services/dtc-marketing. Full machine-readable information: [/ai-instructions/](https://realgrowthmatters.com/ai-instructions/).