THE CAC PAYBACK PLAYBOOK FOR PAID SOCIAL

Most teams kill campaigns too early or scale them too late because they're watching the wrong metric. CAC in isolation tells you almost nothing without payback period and cohort LTV attached to it — a $40 CAC is a bargain for a product with a two-year retention curve and a disaster for one where most customers churn in month two.

We use a simple three-gate framework that forces a decision at fixed checkpoints instead of an open-ended 'let's see how it does.' Gate 1, at day 7, asks a narrow question: is CPA within 20% of target? This is a signal check, not a verdict — at this stage you're filtering out campaigns with fundamentally broken targeting or creative, not judging long-term value.

Gate 2, at day 21, looks at payback period against your cash runway threshold. A campaign can have a perfectly reasonable CAC and still be wrong for your business if it takes 14 months to pay back and you're planning your next fundraise in six. This is where most teams get tripped up — they conflate 'efficient' with 'fast enough,' and those are two different questions.

Gate 3, at day 45, is the one that actually determines whether a campaign gets real budget: does 90-day LTV, measured on early cohorts, justify the spend at a multiple you're comfortable with? We typically want at least 3x LTV:CAC before committing meaningful budget, though the right multiple depends on your margin structure and how much of that LTV is realized in cash versus contribution margin.

Campaigns that fail Gate 1 get killed immediately — no benefit of the doubt, no 'give it another week.' The cost of an extra week on a broken campaign is real budget that could be testing the next idea instead. This is the part most teams struggle with emotionally, especially when a campaign has strong top-of-funnel metrics that mask a weak bottom-of-funnel outcome.

Campaigns that pass all three gates get scaled aggressively, and this is where most of our clients' growth actually comes from — not from testing more ideas, but from having the discipline to put real money behind the few ideas that clear all three checkpoints instead of spreading budget evenly across everything that looks promising on day one.

One caveat worth building into the framework from day one: run these gates on cohort-based data, not blended platform reporting. Platform-reported CAC is increasingly unreliable as iOS privacy changes and cookie deprecation degrade tracking, so payback and LTV numbers should come from your own first-party conversion data, matched back to ad spend by cohort and channel — not from what a dashboard tells you a lead cost.

The framework also forces a healthier conversation with whoever owns the budget, because every kill or scale decision maps to a specific gate and a specific number instead of a gut call made in a status meeting. That matters most when a campaign is borderline — passing Gate 1 comfortably but sitting right at the edge of Gate 2's runway threshold is a very different conversation than a campaign failing outright, and the framework keeps that nuance from getting flattened into a simple 'is it working or not.'