The first overnight of the year
Eleven kilometres out, a lake, and eleven back the next morning. Short enough that nothing could go very wrong, long enough to find what I forgot over the winter.
The tent was still damp from last autumn. Lesson one: dry it properly before storing it. Lesson two: the headlamp batteries do not keep for six months.
Both went onto the checklist, which is now two items longer and probably still incomplete.