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.
Double Edge Razor. I used to shave with an electric shaver but now I can shave faster, better and cheaper. The razor gives a super smooth shave and the soap/aftershave is a kind of wellness routine now that I really enjoy. The blades are extremely cheap so I change them every second shave. There are tons of different types of razors and blades to try out and I really enjoy trying out the shaving soaps and varying them from shave to shave.