Churn kills growth - period. You can bring in a flood of new users, but if none of them stick around, your startup will stall. That's why cohort analysis is crucial. It helps you understand exactly when and why users leave. By grouping users by shared characteristics - like when they signed up or how they interact with your app - you can uncover patterns in behavior that drive retention or churn.

Start with acquisition cohorts to see when users drop off. Then, layer in behavioral cohorts to discover which features actually keep users engaged. You might find that users who complete your onboarding checklist churn far less than those who skip it. Now you've got actionable insight - not vanity metrics.

Use tools like Appcues or Amplitude to simplify the process, and always test your hypotheses before overhauling the user experience. Cohort analysis doesn't just reveal churn- it shows you how to fix it.