I’m focusing on the Ultra here given the cost of the device and the physical robustness of it, but it could in theory apply to any Apple Watch…

One of the criticisms of smart watches is that they are “disposable,” especially compared to traditional mechanical watches. But do they have to be?

1. The Apple Watch Ultra is made of titanium and sapphire glass. My band is also made of titanium. These durable, premium matetials should last for decades, right? Mechanical watches made out of the same grade of steel, titanium also last for decades.

2. The software provides the time, notifications, various complications, and various health sensors. As long as Apple software supports these functions and the electrical systems and chip systems of the device remain intact, why shouldn’t the device be able to do these tasks indefinitely? Lack of ability to these things 5, 10, 20 years from now would seem to be a software decision rather than a hardware limitation.

3. My battery capacity is at 100% after two years. The battery will surely degrade over time. However- shouldn’t the battery be replaceable by Apple (or be replaceable in a future design)?

In short - I don’t see much about the physical device that limits the longevity of an Apple Watch made of durable metal. Any obsolescence seems to really be a software and support issue. Personally I don’t see why I wouldn’t want to wear my current AWU for another decade.

I got the Apple Watch Ultra 3 24 hours ago after being a long time Garmin user. I thought I'd mention my thoughts here in case anyone else was considering.
My previous two watches were the Vivoactive 3 (purchased in 2017) and the Garmin 945 LTE (purchased in 2021).

Pros:

* Smart features are cooler than I expected, it's awesome to have everything perfectly working with my iPhone, being able to reply to messages. Having everything in sync. There is a lot of features, but small things like it being in sync with your Focus. So when my phone is set to sleep, the apple watch goes dark (optional) and gets your ready for bed. Or the reminders app being able to be displayed on a watch face, and I can see how many reminders I have left on my iPhone. Or being able to remote start my car from the watch. Small things which are lovely.
* Data accuracy is great, no cadence lock while running this morning was impressive.
* "Closing rings" is actually quite cool. I thought it would be stupid, in Garmin I was just targeting amount of steps per day. I'm actually enjoying closing rings more than I thought. I think it will get me moving/standing more than Garmin.
* One of the worries I had was the flashlight, I loved the Garmin shortcut to open the flashlight. I didn't have the led flashlight, and didn't want to need to use touchscreen to turn on the flashlight. Turns out on the ultra you can just assign the "Action" button as the flashlight, and it works very well (brighter than my Garmin). I'm sure it's not as good as Garmin's led flashlight, but still very pleasant.
* Cellular on a run is lovely, I used Visible's promo, combined with other promos I was actually able to get an unlimited plan for entirely free for a year.
* I didn't know about "Raise to speak", really cool feature that if you get your watch next to your mouth, you can speak to siri with saying "Siri" or pressing a button. I use it to set timers, or add reminders.
* Touch screen actually works well. I was worried because I hated the touchscreen on my Vivoactive 3. Apple has actually implemented it quite well. Not as good as Garmin's buttons, but still works well.

Cons:

* No workout suggestions by default :(. I loved Garmin's suggestions based on training load, and do intervals and such. There are alternative apps that offer it, but most of them are subscriptions. I still need to try those out.
* There are still several bugs, I've missed some Facebook Messenger notifications that didn't appear on the watch. I have a smart garage, which has an Apple Watch app. But the app just doesn't work, doesn't login.
* The data dashboard isn't as good as Garmin's, you need to look around to find your stuff. Some paid apps try to fix that.
* No animated workouts (I replace with an app with free workouts called "FitOn").
* Watch is heavier than my previous one. (in theory it's lighter than a Fenix, but i never had a Fenix, so not sure how it feels).
* Didn't actually find a watch band I love. Ended up getting the expensive one, which is nice for all day wear, but not that good for running. I'll need to try the Nike bands.