Reinforcement isn't a newsletter. It's a short reminder of exactly the part you skipped.
After the certificate comes the part most trainings skip. For 60 days there is at most one message per week, tied to a module you completed but stopped using.
The throttle on reminders
Whoever doesn't respond gets less mail, not more. Three times no response means stopping. That costs some completion rate and buys calm; we make that trade deliberately.