Retention Rate

What is Retention Rate?

Retention rate is the percentage of customers still active at the end of a period, and in subscription health it is the single biggest driver of LTV and the metric that decides whether a low CAC actually matters.

The formula and a worked example

Retention rate = customers still active at period end ÷ customers at period start. Because it compounds, small differences in the monthly rate explode over time. Work a cohort with round, illustrative numbers. Start 1,000 patients at $299/month: at 90% monthly retention about 531 are still active at month six (roughly $159,000 of monthly recurring revenue), but at 70% retention only about 118 survive to month six. Same CAC, same price, a fundamentally different business, purely on the retention curve.

Retention and average lifespan

Retention is the inverse of churn, and average lifespan is roughly 1 ÷ monthly churn, so the two translate directly into how long a customer pays you. A 90% monthly retention (10% churn) implies about a 10-month average lifespan; pushing retention to 95% (5% churn) roughly doubles it to 20 months, which nearly doubles LTV with no change in acquisition cost. That is why improving retention is almost always cheaper leverage than cutting CAC. The retention and LTV playbook walks through the email and SMS flows that move this number for health brands.

Measure it cleanly

How you count retention changes what it tells you. Logo retention (the share of customers still active) and revenue retention (the share of recurring revenue kept, which upgrades and add-ons can push above 100%) answer different questions, so state which one you mean. And a true cohort measurement (track the same starting group forward month by month) is far more honest than a snapshot rate that mixes tenured and brand-new customers, because heavy first-month churn hides inside a blended average. For subscriptions, watch the month-one and month-three cohort points specifically, since that is where most of the loss and most of the fixable problems live.

Why it matters for health and DTC brands

A GLP-1 or TRT program that keeps 70%+ of patients past month three has a completely different economic engine than one churning 30% a month at the same CAC, and it can afford to outbid that competitor on the identical offer. Treat month-three retention as the gate: if fewer than 70% of patients survive it, fix onboarding and clinical follow-up before scaling acquisition spend, because more traffic into a leaky funnel just buys more churn. Split the two kinds of loss when you diagnose it. Voluntary churn (patients choosing to cancel) points at clinical results, side-effect support, and perceived value; involuntary churn (failed rebills and expired cards) is a payments problem fixable with dunning and card-updater flows, and it silently drives a large share of subscription cancellations. Because retention sets LTV, it also sets what you can afford: model LTV:CAC and CAC payback off your real cohort curves, and check the math with the LTV:CAC calculator.

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