I've had an Apple Watch since the original and have never damaged my watch beyond normal wear and tear microscratches on the metal (not on the face). And I don't use a case. That said, if I were in a pretty physically demanding field, a case might make more sense (my general contractor friend who is frequently on construction sites wears one). I do work out with mine (I currently have the SS) and again, other than microscratches (which I could buff out if I cared) it looks totally fine.