the problem isn't necessarily the fender itself, it's the way assembly line factory workers hurriedly install them. They usually take a self tapping square head screw (usually with no silicone either to stop water wicking) and install it way too close the the edge of the fender which will make it crack where the screw is put in, once it flexes going down the road. With a new fender I'd install the screw further in from the edge, and put a rubber grommet on each side of each screw along with dipping the screws in silicone before installation.