Amazon Prime is particularly heinous about using dark patterns to confound users into risking forgetting but ultimately you’ve already paid for the month, year
I can confirm this to also be the case with most streaming giants plus the less-giant Shutter
Edit: comments have pointed out some notable exceptions such as services through Apple and HP Instant Ink
Napster did this when I went to cancel. They said if you cancel now you lose the rest of the year you already paid for. I set up a reminder to cancel as the time got closer to the renewal, but the service was so bad I contacted customer service and asked for the remainder of my money back that it was unsuable for me. They finally ended up giving me a refund. There have been others, but that one sticks out in my mind.