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.
Holy crap that is amazing! Headphones/earbuds are a big issue for me, partly since I am allowed to listen at work, but I am not allowed to have over ears, but especially since most ear buds cause great pain and inevitable eat infections for me. Thank you so much!
Update: I ordered a pair to try. Twisted my rubber arm.