For years now I’ve had a habit of immediately canceling a subscription service right after I start. Sign up for a HBO Max (Max now)? I spend the extra 60 seconds and cancel that subscription. I’d rather go through the ficiton of adding it back in in 30 days then forget. 

Thankfully most services I use do this (except you Adobe!) and it’s helped me avoid paying for things I didn’t want to.

In the rare event that I can’t cancel, I’ll set a todo on Things for 25 days after I signed up, to make sure I go manually cancel.