Cohort analysis allows you to see how your product changes over time. Are users who joined in January staying longer than those who joined in June? This is the only way to measure the impact of new feature releases on long-term retention.

Retention Heatmaps

By visualizing cohorts as heatmaps, you can spot 'drop-off cliffs'. If every cohort loses 40% of users at Month 3, you have a structural problem with your 90-day renewal or engagement strategy.