Being a person with a nice dark basement and plenty of room, I have always saved a 6 pack of whatever I brew and let them sit, opening in a year or so to evaluate how they stand the test of time.
I found that light brews don't do so well, at least for my taste. They seem to be more susceptible to oxidation as well as bitterness.
However, if you make a good rich stout or porter, a black ale or something with a bit more "meat" to it, they seem to age with some interesting twists, and usually good ones.
I have an oatmeal honey stout that I made 5 years ago that is freaking outstanding now, but I did a Pumpkin spice in 2011 that lost it's spice, though what blended in was pretty nice.
Barley Wines are always best suited to the aging process, but that is part of the norm for them.
I am beginning to limit my "savings" to the higher gravity beers. But I can't resist putting at least one bottle aside for the future. What the hell, makes you keep a "survival larder at the very least!