Everyone carries a saddle bag right? In yours you should have 2 tubes, 2 CO2 cartridges (16 gram) unless you carry a frame pump. A patch kit, tire irons, 10 bucks preferably in case you need to bribe a driver for a ride home. This $10 bill can also be used as a boot for the inside of your tire casing if you get a cut to big for a patch. But most importantly, is the need to have some form of ID and a contact # in case of an emergency. Hopefully you will never need the last item.