What's the advantage of a clean install over a restore when upgrading to a new phone or tablet?

We've had a few people this week ask us about not restoring from their backups when moving from an old iPhone or iPad to a new model. "Is it smarter?" "What data am I going to lose?" "I just want to speed up my device!"

Well, first off: If you're upgrading to an iPhone 7, SE, 6s, or iPad Pro, you shouldn't need a clean install to speed things up — the hardware upgrades alone will do that. But if you're still interested in performing a clean install, read on.

What does "clean install" mean?

When we talk about clean installs, there are two kinds people think of:

  • Reinstall and restore from backup: This is usually done on a single phone or tablet. My iPhone/iPad is slow, so I make an iCloud or encrypted iTunes backup, reinstall and restore iOS, then restore my backup when I get to that part of the setup screen.
  • New device, no restore: This is when you're moving from an older phone or tablet to a new iPhone or iPad. You back up the old device, but set up the new iPhone or iPad as a new device.

What you'll keep and lose when setting up your iPhone 6s as new

Lots of people like this latter "clean install" option for new devices because it allows them a fresh start on setting up their apps, settings, and the like. And while in my opinion no one on iOS needs to do that sort of clean install for system health, there are still those that prefer it.

Thankfully, whether you're doing so because you have too many apps, you want to reconfigure your new iPhone or iPad, or what have you, you won't lose too much information thanks to your iCloud account's syncing features.

Log in with your iCloud account when setting up as new, and here's what you retain:

  • Photos (either the last 1000 or, if you have iCloud Photo Library enabled, your entire library)
  • iCloud email (other accounts you'll have to manually re-add in the Settings app)
  • Records of your purchased apps and app data—no apps will download automatically, but you can go into App Store > Updates > Purchased to restore them on an app-by-app basis.
  • Contacts
  • Some music (All if subscribed to Apple Music; otherwise, purchased music will be available for re-download from the Music app)
  • Safari bookmarks and passwords (if iCloud Keychain is enabled)
  • iCloud Drive documents
  • Calendars
  • Reminders
  • Notes
  • iBooks
  • News preferences
  • Wallet history (but not Apple Pay cards)

You'll lose the following, however:

  • All Health data (only stored in iCloud and encrypted iTunes backups, and you can't restore selectively)
  • Photos not backed up to iCloud Photo Library or My Photo Stream
  • Apps and any app data not stored in iCloud
  • Messages (your archives from your old device)
  • Music synced from iTunes
  • iPhone-only: Your Apple Watch backups (see this note from Apple for more information)

For me, the loss of Apple Watch backups is the clincher for doing a restore over a clean install: I've built up months of Health and Activity data, now, and wouldn't want to lose it. That said, you might not own an Apple Watch nor care about your Health data; if so, you may yet prefer a clean install.

Are you planning on restoring or doing a clean install? Let us know in the comments which, and why.