Everyone has a slightly different kit, I carry one tube, one set of tire levers, I'll add my wallet and keys, this is in an under seat bag, then there is a frame mounted pump, I will add one bottle of water if the ride is supposed to be less then an hour, two bottles if more. Each bike has it's own kit, and it stays with that bike, in fact on the list for next year is another pump for the missus bike, because it does not have one. The MTB has a rear rack, fenders and panniers, and I carry a lock in there, but that bike gets used for grocery runs and other stuff like that....