My AWS will be two years old in July. So far so good. I don't have any scratches on the crystal. In fact I have only one tiny little scratch on the home button. That's it.
I don't baby the watch, and I don't really remove it for many activities. I do take it off while working in the yard/garden. I do that mostly to avoid getting dirt jammed into the mic, but also because I don't want it getting scraped by rocks and tools. I wear my watch while bicycling, hiking, working, chores, sleeping, etc. I do have a desk job, so it's not like I expose it to as many hard/rough surfaces as some jobs would.
I have an iPhone 6 that has a protective display cover that already has a couple of dings, but the watch is fine. I have even knocked the watch into hard surfaces on occasion that I expected to leave a mark. Fortunately they didn't.
Sean