Why customers actually leave: involuntary, never-activated, completed, and dissatisfied churn, read on cohort curves rather than a monthly rate.
Cancellation is paperwork. The decision happened weeks earlier, in behavior you could have seen. Why churn programs that start at the cancel screen are working the least valuable moment in the lifecycle.
A failed credit card and a disappointed customer both show up as a cancellation. Splitting churn into involuntary, never-activated, completed, and dissatisfied is what turns a rate into a plan.