I just carry enough to fix 2 flats (spare tube, patch kit for 2nd flat and inflator with 3 or 4 12G carts) if I'm that unlucky to flat twice I'm bound to crash anyway so I'll be better off walking. also if I'm riding an official montain bike trail people always offer assistance.. on my other rides on 4x4 paths etc I may carry more supplies depending on ride length..