I can't own enough nor stash them in enough places to locate them during setup.
Drum keys are much like 9/16 inch end wrenches, or ½ inch wrenches, they exist in another dimension and can pop in and out of our universe at will... usually at the worst possible time
I try to have a drum key, 3 of them actually, in my pockets. Every pouch in my drum stick back has a minimum of 2 drum keys inside, (and I must have 10 pouches in the bag?). I've got drum keys in my cable bag... mic case, our main gear crate... hell, I have drum keys in every object we have on state, in the trailer, the vehicles we take to gigs AND YET...
It is not rare than I can't locate one, easily anyway.