The gelcoat on fiberglass boats has a UV protectant in it but over the years even it cannot stand up to the relenless damage caused by UV rays. Fortunetly the damage can be undone with the right products and technique. We are masters of making thse old sun faded hulls opo and shine like new.
If you use your boat hard, chances are the gel coat along the keel at the bow and stern will wear through after a few years. The thickness of the gel coat will determine how quickly this happens. Many lightweight boats have thin gel and will wear quickly. Of course you can always launch your boat fully floating so the gel never touches the ground, but what fun would that be?