Ok, that makes sense. Between the plates I set aside to compare with other recipes and my shooting, I make at least one set of plates or batch of film a week. I don't have much space, but I do have the luxury of time these days.
One comment -- plates shouldn't lose density in storage or need to be refrigerated. I have plates that are two years old that expose the same as fresh plates. They have been stored in a light safe at room conditions (which because of where i live never gets really hot, but the humidity is always high). If anything, a plate will gain density with storage. It is essentially continuing the ripening process, albeit very, very slowly. Unless you are maniacally consistent with all exposure conditions, you'd never even notice the difference, especially if you develop by inspection. If plates lose contrast and sensitivity under reasonable storage conditions, it is likely that the emulsion was originally over-ripened after washing, or an additive to the emulsion is causing fogging. An emulsion really doesn't require much beyond the basic ingredients (in my experience, for what it's worth -- but I've made a LOT of emulsions over the last eight years.)
For me it is just a matter of time to use up what I have coated. I figure it's better off cold in the can than finished and coated but I could be totally wrong, too. For some reason I can't get over the idea of shooting frugally like I'm using Portra. I hate wasting film. But handmade emulsions should be shot up and enjoyed. (Actually the Portra should, too.) Once it's gone you get a new excuse to make more.
I don't think there's any question that emulsion is better off out of the can and ready to shoot. It's a trick, though, to flip the switch from emulsion researcher to emulsion user! I certainly struggle with it.
The way I see it, there are at least a couple of reasons to get into handmade materials. The pure love of history is one. Another is being able to fulfill the basic human drive to get really good at something. The history of photography is all about new materials -- rapidly followed by the old materials disappearing. We can take that particular issue into our own hands (unless you're fixated on Kodachrome or other sophisticated color materials.) Make your own b&w negatives and/or paper, and make your own processing chemistry, and you've got your whole life to create your legacy.
The real selling point with a whole lot of people just might be the price point of d.i.y. At 5 bucks, more or less, for a dozen 4x5 plates, "chemical photography is too expensive" just doesn't hold water.
OK, packing up my pom-poms before I start to annoy people :).