My Dad was a Steamfitter and worked all over at refineries in the tri-state area around Philadelphia. His trunk in the 83 5th Ave was filled with a small tool set with sizes matched to what was common on the car Jumper cables, flashlights (2) tire plug kit, tape and tyraps, new belts (Alt/ fan/ powersteering) Plug wires, Cap /rotor, and a set of new hoses. Small floor jack, pry bar, extra lean burn computer. Not too mention premixed coolant, a few quarts of oil and trans fluid... steering fluid washer fluide with de- icer- yes they make that. Hand cleaner, rags and yes... a change of clothes and shoes. The trunk was full with everything one would need to get to work. He never missed a day and 2 plus hours commute was common for him. His 69 Plymouth was a trunk full of stuff too- designed never to get stranded. He did not believe in AAA.
Skip ahead; my trunk on the Volare: Fire extinguishers (2), ballasts (4), ignition boxes (3), various tools to get at the distributor, carb, and brake tools. Flashlight, Cutters/ utility knife, rags, coolant, oil, trans fluid, brake fluid, WD40,tape/ tyraps, cleaner, and a Bible w/ Rosary Beads (Just in case thins get really bad).
When my kids were really small and we would go jeep'n to the store or park- I had food, juice, diapers, toys, extra clothes. Fire extinguisher and a small box of parts like cap, rotor wires, air cleaner, WD40 and about 80 pounds of tools. Going out of the house with a 2 and 3 yearold was like invading Omaha beach.