Do I need a screen protector on my Apple Watch? I am not hard on things.

You have Ion X glass, it is harder to break but easier to scratch. I use Zagg screen protectors on my iPhone, I believe they also sell a Watch screen protector.

I've never put one on it and haven't scratched it, but I do have the sapphire crystal.

I've never had one on any of my versions. I have always had the Stainless Version and I always have Apple Care on all of mine.