One year is more like the protection is so good that you probably won’t even get sick.
I think it also depends a lot on the vaccine though. Something like meningitis or the MMR seem to be much much longer lasting, when you’ve had your shots you don’t need them again.
Probably someone who knows more about vaccines can explain it better.
When you don’t drink often, drinking just a little might not be worth the downsides. You lose tolerance for alcohol fast, and you realise that getting a buzz doesn’t actually feel that great, and isn’t worth feeling worse the next day which can happen after just a couple of beers.