I have about half a dozen carefully boxed and stored in the basement. They are "top-shelf" boards that I cleaned, adjusted, modded, whatever, and used long enough to know that they are absolutely problem-free.
I have another half-dozen floating around between home and work offices, and I rotate them occasionally. I always have an ordinary rubber dome, PS2 keyboard around for testing/maintenance in case any exotic keyboard will not boot .....
There are at least 4 in the garage in pieces, awaiting cleaning, testing, modding, etc.
Since I don't need more than 1-3 examples of any given board, as I upgrade my collection I sell off the leftovers.
I also have several zip-lock baggies full of keys.
My wife is angry about it and says that I should be embarrassed. If push came to shove, I would challenge her to a tally count between my keyboards and her shoes. (I would lose, of course, no matter what the numbers said.)