I have been happily aging beer for years. The oldest beer I have is 18 years old. I have also been happily reading rules about aging beer for years. But it was only when reading this article in the Poughkeepsie Journal, which for the most part is pretty good, that I realized I don't really follow the supposed rules and have been happily doing so for years. Let's look at a few rules:
Corked bottles need laying on their sides: I have caged cork bottles in the stash that are four and five years old and they all stand upright. In Let Me Tell You About Beer from last year, Melissa Cole suggests "cork-sealed bottles need to be laid down so the cork stays moist and maintains the seal." My feeling on the cork is that it is more of a source of risk of off flavours over time than lack of beer is a risk to the cork. Plus, unlike most wines, corks used in beer - like champagnes - are larger than the opening, are caged and subject to back pressure. These conditions keep these bottle sealed more than the wetness of the cork. I have never experienced the suggested problem.
♦ Dark coloured beer ages better than light ones: Never had any experience of a badly aged strong pale ale like a tripel or one of those nutty strong US craft beer anniversary ales. The article in the Poughkeepsie Journal states dark beers "will mellow in intensity" but pale strong beers do exactly the same thing under generally cool and dark conditions. Don't limit your experiments, that's my opinion.
♦ Beer has to be stored in a limited temperature range: In 2009's The Naked Pint from 2009, Perozzi and Beaune recommend investing in a dedicated wine fridge at the cost of $300 to $2,000 because beer should be aged between 50°F and 60°F. My house has a cold room under south-east facing steps. It has air circulation from the outside. It's about 7°F outside right now. I bet the stash experiences 15°F to 75°F over the course of a year. But it does so in a very slow cycle because the beer sits five feet underground. They are also kept boxed and piled to create a thermal mass that would further slow down temperature changes. While protecting the beer, this may actually also result in speed aging. Remember - you want the beer to undergo alteration over time. Why wait by putting the beer in cryogenic hibernation at huge expense?
♦ Don't age beer under a certain strength: Randy Mosher in Tasting Beer also from 2009 states conclusively "...beers with under 6 to 7 percent alcohol are never meant to age." Nothing in life is that certain. My philosophy is that beers at that level and less can shift pleasingly in flavour over time. It's just that they will do it faster. Where I am quite comfortable leaving a 10% beer for years, I'd comfortably leave certain lover strength beers like porters in storage to see if they pick up some tangs. And what about those beers that are spoiled from day one? Old gueuze and other lambics can easily be far closer to 5% than 10%. Again, try it out. See what happens.
That's my experience. Your results may differ and you may have something to add. My idea is that for the most part beer is pretty cheap stuff. Putting away a few wines like I do (in the same space) leads to a small collection with a couple of thousand bucks of investment. Beer? You can have a 200 bottle stash with maybe a third dedicated to long term aging for maybe half that cost. So take a chance. See what happens.