Adam, Keri--
I age roasts on racks on sheetpans with a towel draped on the meat (it gets replaced a couple times a day) and age for, usually, 5 days.
Alton Brown's perforated bin idea is a good one. Keri, Chris describes it
here. The only thing I'd add to it (I'm not sure if AB includes this directive but Chris doesn't so I'm thinking not) is to use a rack in the bin so the roast has good airflow under it as well, something I think is quite important. I have not done the perfed bin thing myself as yet but plan to with my next roast. I have a second fridge I can use for aging, need not access it for anything during the aging process (except to change the towels), so am unconcerned about the potential for odor contamination, dripping or spiliing of other food items, or temp swings sine I can make sure that fridge is clean and ready from the get-go.
The things to keep in mind to prevent aging from becoming rottening:
Your fridge must be able to maintain 34-36 degrees (you can go to 38 but not over that) for the aging time which means that if you have a single fridge you
must set things up so that you minimize opening the door (and when you must open the door it's opened and closed quickly). Frankly, the easiest way to do this is to remove most of the stuff you'll likely want access to and put it in one or two coolers stocked with ice. When I had one fridge I'd move the juices, milk, half-and-half, ice tea, butter, bacon, vegs, etc., to a cooler, and move things I might want (quick) access to up to the top shelf. The aging roast wouls go on the bottom shelf and I'd build a barrier of sorts between it and the door by lining up pickle jars, mayo jars--whatever--sides touching, so that if I needed to open the door the meat woulb be less like to be hit with a blast of warm air and all those cold jars of food would help that area of the fridge return to the proper temp more quickly if the door had been opened (that was my logic anyway). If circumstances are such that you're unable to maintain the proper conditions for aging
do not age the meat.
Do not trim or poke the meat in any way prior to aging.
Aging should be reserved for larger roasts as you note, Adam, not small cuts, though you can age a rib roast, say, then trim it and cut it into individual steaks for grilling.
I've aged large top and bottom round roasts for 14 days--in a commercial environment, not my fridge--with decidedly beneficial results. I've not aged rounds at home nor have I aged chuck roasts. There is no reason that cheap cuts would not benefit from aging though it's true that the benefit might be less (or not at all) discernable if one is braising--as far as flavor goes anyway.
Related sidebar: What we think of as aging is the result of the activity of enzymes in the muscle. Wet-aged meats can develop some of the tenderness and flavor of dry-aged meats (which is why the cryo'd brisket that's benn in your fridge for weeks often cooks and tastes better than one bought and immediately cooked) but not the flavor concentration (since there is no evaporation). The enzymes' (there are two types) activity is dependent on temperature. The activity happens slowly at low fridge temps but low fridge temps are important to minimize bacterial development and high humidity to slow the rate of evaporation. However, enzymatic activity increases dramatically as temps increase. One type of enzyme begins to lose activity at around 105, the other at around 120. Up to these points enzymatic activity speeds up and is the reason why a large roast cooked slowly will usually be more tender than the same roast cooked more quickly. So 'aging' happens with slow cooking as well.
