Cohort analysis sounds like it requires data engineers and a warehouse. The version that answers your most important questions fits in a spreadsheet and takes an afternoon.

The lean approach

  1. Group customers by signup month. Each month is a cohort.
  2. Track retention by month since signup. What percent of each cohort is still active (and paying) in month 1, 2, 3, and so on.
  3. Read the curve's shape. A curve that flattens means you've found a sticky core; one that keeps falling means you have a retention problem, not a growth problem.
  4. Compare cohorts over time. If newer cohorts retain better, your product is improving; if worse, something broke.

Bottom line: a simple signup-month retention grid reveals whether you have a leaky bucket or a sticky core — no data team required.