This whole thing is such a chase-your-own-tail kind of consumerist urging. The powers of marketing are trying to get us all to replace as many possessions as possible as often as possible. I remember when a camera and a watch were things you kept pretty much forever. Meaning: you never had to pay money for a new one. Now they get you to replace your phone as often as possible (I believe the average is every 18 months), and your camera for those who have separate cameras. But the problem with combining everything into your phone is that then you're only replacing one item every 18 months. Solution! Take the watch part back out of the phone and turn that into another thing that has to be replaced on a regular schedule. Because you can bet that even if you want to hang onto it for some epic period like 3-4 years, the software and the apps and all that will have moved on, and it won't be working right any more, and then it will be a $350 piece of junk.
If you put that money in the market, at a modest 5% return, that money will be $525 after ten years. But are you going to stop replacing your Apple watches after they become defunct? Or would you be on the treadmill?
If you bought another $350 watch (let's say the price stayed the same) in another three years, and then that one became outdated and you bought your third in another three years — replacing these things a lot more slowly than they want you to — all that money plus interest would add up to $1397 at the end of ten years. Would you pay $1400 for the Apple watch? Are you aiming at FI? Or would the money better be spent on a vacation you'll remember forever, or some other irreplaceable experience?
Henry David Thoreau found a nice rock and brought it into his cabin on Walden Pond and set it on his windowsill. He was trying to live the simple life. After a while he found that the rock needed dusting. He opened the window and threw it out. "It is best to avoid the beginnings of evil," he wrote.