Originally Posted by
BigAura
+1 I would say that a standard multi-tool can handle 90% of all repairs.
If you start a X/C trip with a properly built bike, with new tires, chain, cables, brake pads, and good drive train, you could probably leave all tools (flat change tools excluded) at home. Especially the ones you don't know how to use. If you add to this stopping at a bike shop once or twice for a check-up, you'll reduce your break-down odds to miniscule. I would contend that this applies to UL or fully-loaded tourers.
I wouldn't want to leave home without a chain tool. It's rare, but a chain can just break and I want to be able to put one together to get me to the next bike shop.