Despite their stupid cost I still keep mine every time. Just had them so long that I never want to get rid of them.
Long story short, 20 years ago I wanted a different plate. The ones I have now were my second choice. The original ones I wanted were taken in between me checking availability and having a vehicle to put them on. I could never find out who had them. Few years ago went to a good friend's house, he opened his garage door where his "race car" was parked which I had never seen before, he had the plates on it. Turns out 15 or so years before we ever knew each other he snagged the plates up for his race car.