I bought a piece of 1.5 inch stiff foam to try to fix a sag in a bed. It didn’t work but having that thick piece of solid foam around has been a life saver.
Need something flat to put a laptop on? Throw it on the foam. Going to be doing something that requires you to be on your knees for a while? Get the foam!
It went from stupid purchase to something I’d gladly replace if it broke.
I don’t really care about the feel of a keyboard, but the fact that you can replace a broken switch is very amazing. Previously my membrane keyboard only last for about 1-2 year before I need to throw it away because some of the key stop registering. Now I can just replace the switch for <$1