Yes and no. Most CF have UV inhibitors. Aerospace grade CF prepregs are treated. You think the UV exposure at sea-level is bad? Think about what happens when you're several miles up. They use CF in commercial airliners and those things aren't exactly designed with only a year's lifespan. Most quality CF bikes I know of use aerospace grade CF like Toray's T700. And yes, UV protectant clearcoat is also often applied as another protective measure. it's pretty much a moot point. It's like worrying about corrosion or rust with other materials. The thing you have to worry about with CF is QC and how it was made. Reputation of the manufacturer counts for a lot in this case. A well constructed CF structure can last as long if not longer than those made of steel and titanium.