I learned from Karl Striedeck that you should have a post-flight
checklist that includes items to take out of the sailplane including
wallet, batteries, logger, maps, turnpoint data, water, food (no
mice!), reading glasses, pee thang, etc.
Add any special rigging tools and pins that you want back into the
fuselage, not left on the ground after an off-airport retrieve, in the
dark, in the rain.
You can add more -- some are especially important if you de-rig every
night.
Digging wallet out of the fuselage inside trailer in the dark, or in
the rain . . . been there.