I do, for the same reasons you said. When I have a color in my stash, I tend to use it and use it until it and all the stash that "goes" with it is used up. Then, the next major project starts the whole thing over again.
But still, my stash tends to revolve around my personal favorite color ways. For me that's anything blue, blue-reds, (not orangey reds) and cream/tans. Oh, and anything purple of course!