I've only come back to the Apple Watch about 2 weeks ago. My last one was the Series 4 and I stopped using it after a year as UI wasn't seeing the benefits of it. And I was more of a mechanical watch guy. I then had to get a health tracker after having a heart incident, but chose the Fitbit Charge 4, which is a really great watch and very much recommended for health tracking, and it has a 5-day battery life. It will also give you notifications for messages, calls, etc.
As I am deep into the Apple ecosystem, I decided to give the AW another go with the launch of the S11. The always-on display was a real benefit for me, and the addition of a few Fitbit-like features on health really swung it, like sleep scores, vitals, etc.
It's been a very pleasant reunion. One thing I had forgotten was Apple Pay. I love that feature and am always impressed with how well it works. It works every time, just having it anywhere near the credit card reader, and it's done. I find it easier than the iPhone. Went shopping today, and my shopping list on Notes worked a treat, with being able to check each item off the list. The cellular option is great, I use it all the time now when exercising and can leave the phone behind. That's great. Basically, I'm using the watch a lot more than I thought; all the added benefits aside from the health stuff are superb.
One thing to note, I still have the Series 4 and decided to give it a trial run to help me decide going for the S11. I was very impressed with how well that watch held up. Screen still looks great, all the functions still worked, battery life was even OK.