If you are a solo rider (or with improperly equipped friends) and take only CO2 cartridges out into the wilderness (i.e., no friendly people to help out), I would seriously consider taking a pump along. I have flatted both tires at once (staple in one and glass in the other), plus you can't help out anyone on the road. I'd feel like I had to conserve my CO2 just in case. A pump will get you home every time even if the pressure isn't as high as you'd like. I always have a patch kit along so I can help out others or if I go through my lone extra tube.