Originally Posted by azwhelan
I carry 3 or 4 cartridges. If I need more than that the cycling gods are against me and I'm calling in the team car(wife) for ride. On a group ride everybody has co2 because it would be inconsiderate to make everbody wait for you to pump. It also means if you run out of cartridges there's always somebody there to offer one up. I bought a couple of boxes when I first got my bike 2 years ago and still half of those so the cost is minimal unless you're having a string of bad luck.
I only carry two cartridges, but otherwise I agree with the above post. I don't have a wife, but I can always call a friend if need be. They are quick,easy, fill to high pressures, and almost everybody else has them on a ride. In two years, I've only used three of them total. So why carry around a pump that I have to work to get up to 110-115 psi with, when I can do it effortlessly in seconds with C02. That's why I do it anyway. But to each his own.