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.
They hide their in depth graphs and readings from you unless you pay for premium. You can get basic data going back years, but if you want to know how long it took you to enter REM sleep for example, your only option is trying to guess using their vague graph charts, or pay premium for the in depth graphs.