I have heard that too, probably part of the built-in obscelence plan! Though I think battery life goes down regardless. I have also heard that the processors have to be slowed down in the older phones slightly as otherwise with newer os and software they might run to hot and explode either figuratively or literally (which seems to be a thing that Surfaces and Samsungs do). Having done no research at all on this I have no idea which one is more true.

Thinking about it I'm pretty sure the MacBook Air is entering its fifth year too, as I think I got it kind of in a hurry for the last time I was heading home which was 4 years ago. Still going reasonably strong, little bit laggy but I don't know if that's from built in obsolescence, the fact that I've dragged it through three major OS updates since I got it and I think there's more eye candy in each one (I love eye candy XD) or just general age.

If you don't need the power, a laptop would definitely work better precisely because you can just haul it around wherever. My sister mains a laptop (16" MacBook Pro) and it does her fine, she can just pick it up when she's coming out to the mainland for her annual holidays and then head back home with no disruption to her artistic schedule. I was semi-contemplating seeing if I could do the same but I feel like I would almost definitely melt a laptop XD

I generally start saving for a new one the moment I buy a new one knowing that I'll need a new one when my current new one isn't a new one any more

SAME!

Except I haven't had to do that anymore because J promised when I went down this route that he would do the tech support side of things (because I don't really have time for the research and build process anymore), so after a few years when I start having minor performance issues he does the research and I get part upgrades and then everyone else gets upgrades from my operational leftovers.

So there's that if you like the build/repair side of computers but maybe not so much if you don't XD