Ask me about Piriformis syndrome
Very few....just don’t have the space. A derailleur, bar mount shifter, dropper, chains, inner cables, f/r brake levers, one caliper, basic tools.
Felix and I run pretty much everything the same spec, size and diameter for ease of spares.
You’re self catering/Accomodating though, aren’t you? If I was in a car/van/camper, I’d bring 3 of every bike part in the world.