Churn, a key metric for startups, is often misunderstood and misinterpreted. To truly understand churn, it's essential to consider various factors such as revenue churn vs user churn, activity churn, and the impact of churn on customer lifetime value (LTV). Activity churn, which measures the decrease in usage over time, is a more effective indicator of future problems than traditional metrics like account cancellations. Identifying and addressing drops in team-level activity can help re-engage customers, while well-timed personal emails can also be an effective strategy. Effective communication with customers, including being personal, interesting, visual, thankful, honest, and respectful, is crucial for reducing churn. By understanding the impact of churn on LTV and adopting strategies to engage customers, startups can mitigate its effects and drive business growth.