I usually carry WAY more than I ever need. In cases of emergency I try to have the little things that will keep me flying. I always take two planes, just in case one has problems I CAN'T fix at the field.
Water, food, chair, sunscreen, hat, sunglasses, and a charger. Plus the required field equipment. Baby wipes for cleaning the planes ( and me). A cell phone...JUST IN CASE...my wife calls, heh heh. Anyway, carry what you feel like you might need to make your day at the field. I suppose I am a "minimalist". I try to travel light when I can.