I have a short commute (3 miles) that is entirely on bus lines, so I carry nothing extra. If I hasn't meetings off my route or travel to a field site, I am prepared for flats (tube and pump), but rarely carry more than that. The only repair that this preparedness had bit been able to fix would not have been repairable with my touring toolkit; a stick destroyed my rear derailleur and my chain foot bent (didn't know before that the latter was really possible).