The full cycle.
WHAT TO TEST
Signing up Initial payment Access granted Renewal charging correctly Failed payment handling Updating payment details Changing tier Cancelling Access ending correctly
THE RENEWAL TEST
The one people skip, and the one that fails.
Use test mode with a short interval if your gateway supports it.
THE CANCELLATION TEST
Confirm access actually ends when it should, and not before.
A customer losing access mid-period they paid for is a serious complaint.
THE FAILED PAYMENT TEST
Deliberately fail a payment.
Confirm the retry, the notification, the grace period and the suspension all behave as intended.
Most people have never seen what their own system does here.
WHAT ELSE TO CHECK
Every email sends and reads correctly The customer portal works Records match between your site and the gateway
WHEN TO RETEST
After any change to the site, plugin or gateway configuration.