Armpit

The stems (on the key cap, not the keyboard switch) crack and break, the switch post is fine and the key works but the key cap just falls off with bits and pieces of the stem left behind. And no, I do not use O-rings or anything like that, and the keyboard is not exposed to direct sunlight ever.

I just had my third keycap break on me today. Very annoying and the odd thing is they're breaking randomly even on keys that almost never get used (like the Pause/Break key or the period key on the numeric pad) so it doesn't seem to be use related. I don't clean the keyboard and I haven't really pulled any of these keycaps off before so I have no idea what is going on.