The day you don't bring tools on the trail is the day you'll break down, so stick the Crank Brothers Multi-19 Tool in your pack as a prophylactic, at the very least (but not that kind). Even if this have-it-so-you-don't-need-it voodoo doesn't work, you'll have 19 tools to fix whatever goes wrong, from loose bolts to shakey spokes to broken chains. Seven hex wrenches take care of most issues, while the screwdrivers, open wrenches, Torx driver, and spoke wrenches handle pretty much anything else short of a broken frame, in which case you'll be walking home no matter what tools you have.