This document discusses different types of churn that companies should measure to understand customer retention. It defines customer churn as the percentage of customers lost over a period of time. Revenue churn measures the percentage of annual recurring revenue lost from churned customers. Monthly subscription churn isolates churn for monthly subscribers. Net churn considers both monthly churn and new revenue to assess a company's overall health. The document emphasizes that looking at multiple churn metrics provides a fuller picture of customer retention than a single churn rate.