Retention

Retention tracks whether users return — day over day, week over week, month over month. It is the truest test of value: acquisition and activation get people in the door, but only a product worth coming back to holds them. A flat or rising retention curve is the strongest evidence of product-market fit.

Retention and churn are two sides of one coin. Because the cost of keeping a user is far below the cost of acquiring a new one, small improvements to retention compound into outsized effects on growth and unit economics.

In practice

A team plots weekly cohort curves for the first time. The shape tells the story: curves drop steeply for three weeks, then flatten around 35% — users who survive a month tend to stay. Digging into what the survivors share reveals one habit: they set up a recurring report in week one. That correlation redirects the roadmap — instead of new acquisition features, the quarter goes to making recurring reports the default path, and the flat part of the curve rises cohort by cohort.