The letters on my keyboard at work are slowly getting rubbed off by my typing. The ‘e’ and ‘t’ keys are now completely blank, and ‘i’ is almost there. It will eventually be completely letter-free (though that may take another year).
I type with the Dvorak layout, so ‘e’ and ‘t’ for me are where ‘d’ and ‘l’ are on a qwerty keyboard. Since I can’t look at my fingers to know what to type anyway, having this keyboard end up completely blank would be fun.