Shoes

Your feet keep a fairly accurate record of what you’ve been putting them in.

Corns, calluses, blisters, damaged nails and gradually changing toe shape are not random. They form where pressure and friction repeat, and pressure and friction repeat where a shoe doesn’t match the foot inside it.

Which means you can read the problem backwards. Find the mark, work out what’s causing it, and you’ve usually identified the shoe feature that needs to change.