After three years of hard service I finally retired my series 0 watch. I went out to the Apple store last week to pick up another USB C cable and while I was waiting I was playing with the watches. After a couple of minutes my mind started to contemplate the benefits of upgrading. long story short in addition to the cable I also walked out of the store with a new watch. I did a couple of things different this time. the biggest change for me was going from 38mm to 42mm. while I never had any complaints about having a 38mm before I always lusted after the 42 as it looked better on my wrist. Another change was going from a space gray to a silver watch. That was the one regret I had on the S0 as within a couple of months of use I was starting to notice little chips in the crown and around the edges. The biggest changes that I've noticed on the new watch are speed and battery life. now my S0 wasn't my original launch day watch, I had to have it replaced in August 2016 due to a cracked screen. Even though the watch itself wasn't quite 2 years old yet the battery life was really getting to be a limiting factor for me. My normal wearing hours are 6am to around 11pm and it was either in battery reserve or about to be by 6pm-ish. battery life was actually the biggest reason for upgrading. My new watch barely uses 15 percent in the same day that my old one used the whole battery. the speed improvements are also very very nice. it no longer takes forever to load anything and I'm actually more likely to do things on my watch now because of it. I opted for the GPS model over the LTE mainly because Im never away from my phone so it didn't seem like something that I would be missing and so far I haven't had one time where I wished I had it. I'm still using my S0 at night for sleep tracking and as long as I have it in silent and theater mode it makes it through the night so I think as long as its supported by my sleep app ill continue to use it for that. one con for upgrading is in the past three years I collected a lot of different bands from the sport band all the way to the link bracelet being 38mm I thought that the wouldn't fit on the 42mm however they do fit and they look okay but you can tell they aren't for that size watch. So for those still rocking the S0 and are thinking of upgrading I would highly recommend it.