Not sure where you're getting that information but I've had Bushwackers on my Jeep for at least 5 years, my Jeep is always parked outside in the California sun and they've held up great. I've done a couple of trips on the Rubicon Trail, rubbed up against a few rocks and trees over the years, and they didn't get any cracks. Ultimately I think I want to replace them with aftermarket steel fenders but those are more of a "solution looking for a problem" in my case because I'm not having any clearance issues with my current setup. Besides, I have a few other priorities for my Jeep, like new PRP seats and replacing the lunchbox front locker with an ARB.