A:
I had never looked for a date before, but I see that the box (NOT the cartridge) for my most recent purchase does bear a human-recognizable date (about seven months old).
I've never thought I had a problem with "settling," but I think the question is almost irrelevant, as one ought to rotate the cartridge vigorously before breaking the seal (I know I always do--have been doing so for at least twenty years with all laser printer toner cartridges)
Answered on 8/2/2010 by Rollie from Madison, Wisconsin