[elesiuta]

> I get that they're not the same device, but is it really 2.1x the device that the 13 is?

It looks like you're using an average lifetime of 9 years for the 2.1x factor. I rarely see phones past 6 though and that's approximately how long they receive updates for.

I've also never seen a used iPhone that cheap where I am. Here a new 15 max is $1450 and a used 13 max is $1000.

Using a 6 year life:

$1000 / (6-2) = $250

$1450 / 6 = $242

So if you use a phone to the 6 year point, you are paying less for a better device, and without any unknown damage or wear. Migrating less often to a new device is also a small time saver. Even if you go to 9 years, the new iPhone is only 1.13x more.