Got my Series 0 Apple Watch in July 2015 and loved it. I pretty much stopped wearing it mid 2017. Seemed as though the battery had gotten so bad it was unusable. I then determined that a certain app was one of the main culprits in draining the battery. App in Air which is a great app when traveling by Air. So I just lost interest in wearing it the rest 2017 and most of 2018. Had no interest in the Series 1,2,3 or 4. So after getting the XS Max I decided to give my Series 0 another go. Ironically my watch had been on the charger for months without any adverse effects and it was always synced to my 7 Plus which I had before the Max. After setting up the Max the watch was synced to it and I found the battery life was terrible. 4 hours and it was almost drained. 50% drain in 2 hours. So I did a erase and reset of the watch and didn’t install a bunch of apps just kept the basics. Messages, Calendar, Weather, Mail etc and my Series 0 got new life with 20-22 hours of battery life. In 2015 I was getting about 24 hours with a bunch of apps I did really use. So I’m back to wearing it as watch and getting messages emails and certain notifications like taking medications. Maybe I’ll get a Series 5 whenever that comes out but right now my Series 0 is good for what it can do. I even feel better about getting a Sport loop band it.