95% of the time I never have any trouble finding a leak fast (and 3% of the time it takes more patience) on the road; thus I can save weight and bulk by only having to carry 1 tube...of course I make up for the lack of 2 extra tubes by carry a spare ultralight racing tire! When you ride out in the middle of nowhere as I like to do and have had tires get destroyed, then having a spare tire (and of course a tube) is a life saver.