1 have two 13s and have never carried a spare belt and have never needed one, i have never had to change a drive belt on the mountain either , i will carry one for the group 4 pros ,with one turbo-ed never a whiff of a problem , i love it that your so convinced of how much better cats are than pros. in my experience after having cats for over 20 years the pro is a far superior both in build quality , performance and engineering.my m1000 was regularly beaten by my friends 11 pro and he didn't have to carry extra gas extra belts (which regularly blew) steering posts ,(broke 2) , then after repairing a damaged 13 turbo-ed 4 stroke and experiencing for my self the way they were put together with hundreds of screws and piss poor engineering, a hood that was an absolute joke to put on , and clutching that was even worse than my m 1000 (if that was even possible). i will not be going back to cat any time soon , and if i owned one i would not be going all over the internet saying how much worse the other brands are .