The main revenue generator for subscription businesses is recurring payments. There might be additional one-time offerings but the number of subscribers opting in for additional charges is limited and this number will be harder to predict. That's why the financial health of a subscription business can best be measured by the retention rate. If the users are satisfied with the product or the service, they will likely stay until their needs change. That's why it is important what kind of retention features there are in an app and how these are presented to users, especially the ones who are entering a cancellation funnel to end their recurring payment cycles. 

To quickly visualize this, businesses utilize Time-Based Cohort Analysis. The cohorts consist of users who signup in a particular time frame which might have a granularity from weekly to quarterly. For each cohort, the percentage of retained customers are calculated in every time period until the most current.

This repo explains how pycohort is created to create simple cohort visualizations.