Cellaring and Aging Beer - Imbibe Magazine
I think it's more of a guess with style and expectation at this time, based on some people who have managed to age some styles. It's not been something that has been widely done, though is becoming more common.
My brother just opened a 5 year old Trader Joe's ale on Thanksgiving, I'm PO'd that he didn't taste it, but instead let the others try it. (I'm allergic so I'm void). New Beer: Trader Joe's 2011 Vintage Ale | Serious Eats: Drinks
You'll see that others have done the same and commented.
In part, some has to do with the higher alcohol levels and possibly lower hop styles. But at this point, who really knows for sure. I apparently have some simple Leinenkugels from a variety case and a few stouts from back when I wasn't allergic 9 or so years ago, and I've been told they still drink well. (I was going to dump them just for the bottles, glad it was tasted by someone willing. Instead I left them in the cellar.)
Secondary: GF Czech Lager
Waiting to be kegged, Italian Primitivo
Kegged&Ready: GF Orange&Coriander, GF Honey Lager, GF chocolate ale, GF English ale, Island mist (zinfandel), Island mist (cbry malbec).
Bottled: Infected Mead, Dry Hard ciders, Accidental Sorghumwine, various unnamed.