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.
Lol I have one but don't notice the difference. I mostly bought it because my husband tends to overdo things (like more coffee in the grinder, grinding longer). So I got it so he'd only have to press one button and we'd get consistent coffee. What difference do you find with it?