not technically a poll: How long does beer last?

Brendan and I are contemplating the contents of the basement fridge, which includes Bell's Oberon (a summer label) and other beer we know is at least 6 months old. Is this beer past servable? Should we toss it? Neither of us are beer-drinkers, so we don't know.

I wasn't up to making poll options, so please just comment. Thanks!