Originally Posted by Blue Order

Carbon and aluminum both develop stress fractures with use. The lifespan of a carbon frame is very, very short. Aluminum also has a short lifespan. Now, I think with little use, alumnium will have a longer lifespan. I'm not sure if that's also true for carbon-- meaning I don't know if the plastic breaks down with age, or only with use. Steel can take whatever use you can dish out, and if it does somehow break, it's repairable. Carbon and aluminum framesets are are throwaways once they develop those stress fractures.