7. Key Magnet
I always keep a spare key hidden somewhere on my vehicle. I don’t use a magnetic key box because it can fall off, and it’s not easy to find a place big enough to stick them to mostly plastic modern cars. Instead, I bolted my spare key to a magnet, the kind with metal on one side and a hole in the middle. It fits perfectly in a little nook near my rear bumper, and it’s been there for years without falling off.