I had an Apple Watch on the first day the first model was available. Moved to Series 2 which was clearly better, but have stayed there. I live in NYC where free wifi is everywhere and I’m never going to get stranded miles away from another person. Cellular service on my watch is simply not something I need. The time needed before the battery needs to be recharged is important when traveling but something that’s easy to plan around in my daily life. But I watch every Apple announcement about products I use and certainly find the Apple Watch Series 4 fun. Bottom line, however, for me, is that it has a busier watch face, alerts me to a change in a medical condition I don’t have, and could call emergency services if I fell. None of those are enough to make me rush out to replace my current model.
If your decision tree is less straightforward, these articles may help:
(1) How to sell the one you have? https://www.cultofmac.com/578155/best-price-for-apple-watch/ Cult of Mac has a buying service that it would like you to use, but also mentions the other major players and some good advice.
(2) How to set up the Series 4 to respond as you want it to if you fall.
https://www.cnet.com/how-to/apple-watch-series-4-how-to-enable-fall-detection/ Anecdotally, Apple spent the time so that it’s very difficult to trick the watch into thinking you fell. If you buy a Series 4, this setup is definitely part of your immediate future regardless of your age.
(3) For fun, any Apple Watch after the first model (so including Series 1, but not before) into a walkie-talkie (I shudder at the possibillities).
(4) A fairly rapturous review of the Apple Watch Series 4 from Wired.
(5) And the view of the New York Times.