[Symbiote]

I don't really want to see a bill for e.g. £0.41 every month on my credit card statement, and at some point the transaction fees would become a bother for Signal.

I'd have ticked "recurring annually" if the option had existed.

[alias_neo]

Set up a recurring calendar reminder. Maybe boxing day or new years day and give yourself a fresh start to the year with some donations.