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.
For people asking for the link, I personally have iClever BK03. Bought it so I can use my phone on the go and don’t have to drag a laptop. It’s been great. Charged it once so far in past year or so and that was just to make sure. Awesome build quality and great to type on.