[barkerja]

> In many cases, they're not 'perfectly good'. Apple does backwards compatibility longer than most, but at some point, those old phones can't function as smart phones. Banking and health apps will require newer OS, and newer OS eventually means new device (for better or worse).

To add to this, each annual release of iOS does typically add a new feature or two that works only on the newest model(s). Sometimes, this is enough to generate an upgrade.

There's also a large amount of people that essentially "rent" their phone through a consistent upgrade pipeline via their carrier or Apple directly (basically never paying off the device directly).