Man, y'all seem to be a lot better than I am at keeping your keyboards alive:
My first was a Ducky 1008XM, which died after a few months.
Then my second mech, a MicroConnectors D07-135 died in an attempt to use its parts to fix the Ducky. Admittedly that was a very cheap keyboard and only ever intended as a stopgap, while waiting for my third mech, a Noppoo Tank that I've still got somewhere (though it has a bit of chatter, which gets annoying). Who knows how much longer that D07 would have lasted, though-- I bought another one years later, because I dig simplified black ALPS, and it didn't make it very long before suffering spontaneous complete failure.
If you count Olivetti dome with slider as mechanical, I killed one of those, too, trying to splice its switches into an iRocks dome board I had lying around. That didn't go well for either of them, though I do think that, with tools and skills (I have neither), it could be done.
Fourth or fifth, depending on how you count, was a Model M, which I've only managed to mostly kill. Still around until I manage either to fix it or finish it off in the attempt.
Then fifth or sixth was a Das Ultimate, which dropped dead after a couple of years.
...and so on.
