I'm still drinking most of my beers at 1 year, often at 2. IPAs and PAs usually get drunk within a couple of months, but everything else takes a while.
I rarely make a beer less than 6%, so that helps. For the most part, I find the beers keep well, obviously changing over time. I wouldn't say they necessarily get better or worse, they just change, and that is Ok for me.
In the last 150 beers I've brewed, I've only had one that has been a drain pour after a year or so. It was an 8% Belgian, brewed with a large percentage of grape juice. It was a fantastic beer when initially brewed. I recently discovered 2 Bombers hiding away that were about 18 months old, and they tasted awful. I'm suspecting it had something to do with the grape juice.
Never dump a beer until you have tried it.
... That reminds me, I think I have a 10 year old case of 13% Barley Wine hiding among my sours that I will have to dig out.