I don't have EPO rudders but was considering buying a set. Are they especially brittle or something? I always let the shore kick up my rudders.
They are certainly not as tough as the stock nylon rudders. They don't flex - that's why they handle so much better. They're essentially fiberglass(carbon) and have a gel-coat like outer "skin". Rocks will chip them. Sand will make the clear coating turn hazy. You don't want to wear them down to the fiber, either.
I don't know about you, but I'm not dragging my $250 (each) rudders along the bottom. It's too easy just to pop them up before you hit.