Retention
Why users come back — and what it reveals about the value they actually get.
Growth gets users in the door. Retention tells you whether the product was worth walking through it.
What retention actually measures
Retention is the share of users who come back and keep getting value over time. It's the closest thing product has to a truth serum: acquisition can be bought, but sustained return has to be earned by the experience.
It's read as a curve — what fraction are still active after a day, a week, a month. A healthy product's curve flattens into a stable plateau; a leaky one decays toward zero no matter how many users you pour in.
Growth vs retention
Growth
How many users arrive.
- Can be paid for
- Spikes on launches
- Hides a leaky product
Retention
How many stay for the value.
- Has to be earned
- Reflects real fit
- Exposes a leaky product
Core insight
Before you optimize growth, ask whether the retention curve has flattened. If it hasn't, growth is the wrong problem.