I can't think of a time I've wanted to reinstall the OS. I've wanted on several occasions to factory wipe the device (trading in the phone, fresh start, repurpo

I can't think of a time I've wanted to reinstall the OS. I've wanted on several occasions to factory wipe the device (trading in the phone, fresh start, repurposing it, etc), but "Reset all content and settings" is an option locally on the device. As far as backups: as a matter of general data hygiene I don't let my iPhone or my laptop be the source-of-truth for anything. Contacts sync to iCloud and Google, Photos to Google and Dropbox, etc etc.