What is Retention Rate?

Retention is often more important than acquisition for long-term business success. Research shows acquiring a new customer costs 5-25x more than retaining an existing one, and increasing retention by just 5% can boost profits by 25-95% (Harvard Business Review). This is why retention rate is considered the most fundamental product health metric.

Retention curves show the percentage of a cohort that remains active over time. A healthy product shows a retention curve that flattens (indicating a core group of loyal users), while an unhealthy product shows a curve that continues declining toward zero. The shape of this curve reveals whether the product has achieved genuine product-market fit.

In case interviews, analyze retention across dimensions: by customer segment, acquisition channel, product tier, and time cohort. This reveals whether certain types of customers are better fits and whether retention is improving or deteriorating over time. Strategies to improve retention include enhancing onboarding, creating habit loops, building community, personalizing experiences, and implementing loyalty programs.