The short answer is that yes, beer expires. But saying the beer expires is a bit misleading, it doesn't actually become unsafe to drink, it just starts to taste unappealing or flat.

How long can you keep bottled beer?

Kept in a dark and cold area, like a fridge, bottled beer will last up to 6 months. Stored warm, bottled beer can spoil in as quickly as 3 months. Keeping beer bottles away from light prevents the development of skunky off-flavors. Beer is extremely sensitive to light.

Is it safe to drink 10 year old beer?

The simple answer is yes, the beer is still good insofar as it is safe to drink. Since most beer is either pasteurized or filtered to eliminate bacteria, it's extremely resistant to spoiling. How the beer will taste is another matter.