Anonymous
Favorite Answer
The darker and stronger the beer, the more likely it is to peak after the first year. Hoppiness helps too but the beer I won't even touch for a year or two is spruce beer, which contains no hops at all. The spruce extract, like hops, acts as a preservative. As far as "how long" goes, You just have to keep sampling your beer until it reaches its peak. A tough job but somebody has to do it.
Flavor Vortex
Barleywine is beer and yes you can age it. As a rule of thumb beers that are high in ABV (like wine) or high in alpha acids (hoppy beers) tend to age more gracefully than most beers. This includes, but isn't limited to, imperial stouts, barleywines, old ales, and various stronger Belgian styles. Much like wine though cellaring is a trial and error process, there's no guarantee you'll wind up with a better bottle in 5 years than you would if you just drank it now.
Anonymous
Yes.
Many stouts, porters, Imperial stouts, Belgian ales, bocks, and other styles can be aged for years.
http://www.allaboutbeer.com/features/233belgianagedbeer.html
http://www.russianriverbrewing.com/web/barrel.html
http://beeradvocate.com/forum/list/29
http://www.beercook.com/articles/woodale.htm
Beer can be aged and it may improve with age but not always. Sometimes the beers break down into off/poor flavors. The good news is the heavy (specific gravity-alcohol-bitterness) beers often mask these off flavors.