This is the key. I have a SS Apple Watch series 0, preordered and received on the original release day. The watch itself is still holding up great. Minor scuff marks, but I wear it everywhere, including during military training. The screen still looks as good as it did on day one and it holds up great. After 24 hours of straight use (charge it before bed, wear it for sleep tracking, 45 minute workout, and out and about all day) and it finally gave a low battery warning around 8:30 p.m.
That said, the actual usefulness of the watch is almost completely gone, except for telling time. This is solely due to the speed of the watch (or I should say a lack thereof). Apps are constantly freezing and taking forever to load. I recently started getting back into working out and used Strava for running. Very slow, and if I raise my wrist to check my time/pace/distance, it takes a good 10 seconds to update. Not ideal when you are holding your wrist up while running.
This morning, I attempted to start an "other workout" using Apple's own fitness tracker. I had already started my workout and forgot to start my watch. I went to Activity and after about 30 seconds of hanging I gave up and reset the watch. Oops. Timed the restart (I was doing circuits) and it took just under 3 minutes before it started back up. Activity did work fine at that point.
The main issue here is that doing anything except checking notifications and time takes so long it is just much easier to do it with the phone. The watch faces, which I first loved, have gotten extremely stale and boring. I like fancy watch faces, and the Apple Watch does not have any that look even remotely realistic. Take a look at the new Samsung Gear and you will see what I mean.
I am holding on to my AW0 for now. Can't really justify paying for a new one ATM. It still works good for tracking steps throughout the day and for basic activity tracking. I also use it as a sleep monitor where it excels. This latest OS (Watch OS 4?) is what really killed it. So to me, what would be about the real useful time of the watch as a smartwatch. It is still more than useful as a slightly more than basic watch. And, or course, all three bands I purchased with the watch (Milanese loop, leather loop, and white sports band) are in excellent condition! :-D