Clean the old phone before you transfer, not after. Trimming 15-40 GB of duplicate photos and forgotten 4K videos first means the migration copies less data, finishes faster, and you don't drag junk onto a fresh device. Most people can cut a third of their used storage in under 20 minutes.
TL;DR
- Clean first, transfer second: every gigabyte you delete is a gigabyte you don't have to copy or back up.
- Start with the heaviest items: large videos and duplicate photo bursts, not single screenshots.
- Back up to iCloud or your Mac after cleaning so the backup is small and quick.
- Quick Start transfers everything as-is, so anything you don't delete rides along to the new phone.
- Deleted photos sit in Recently Deleted for ~30 days, so you have a safety net before they're gone for good.
How do I see what's actually taking up space?
Open Settings > General > iPhone Storage. Wait a few seconds for the bar to load, then scroll the per-app list sorted by size. Photos, and sometimes a single messaging app, usually dominate. If you're surprised by a big chunk you can't account for, that's worth a closer look before you move it across: iPhone storage full but nothing to delete: what's actually using it.
How do I cut the biggest videos first?
In Photos > Albums > Media Types > Videos you'll find your clips, but they aren't sorted by size there. The fast win is removing the few multi-gigabyte 4K recordings you'll never rewatch. A focused walkthrough that protects your real photos: how to find and delete large videos on iPhone without deleting photos.
How do I clear out duplicates?
iOS has a built-in tool: Photos > Albums > Utilities > Duplicates. Tap Merge to combine exact and near-identical copies. It keeps the highest quality version and moves the rest to Recently Deleted.
What iOS does natively, and where it stops
Natively, iOS finds exact and near-exact duplicates and offers offload-unused-apps. That's genuinely useful. Where it stops: it won't surface your largest individual videos, near-miss burst frames that aren't flagged as duplicates, or the blurry and screenshot clutter that adds up. It also can't rank everything by size in one view. Cleanor closes that gap by scanning on-device and sorting your library by what's actually big and redundant, so you decide in one pass instead of hunting through albums.
In what order should I transfer?
- Clean photos and videos (steps above).
- Settings > General > iPhone Storage and offload any app you won't reinstall.
- Back up: Settings > [your name] > iCloud > iCloud Backup > Back Up Now, or plug into a Mac and back up there.
- On the new iPhone, use Quick Start (hold the two phones together) or restore from that fresh backup.
Because Quick Start and backups copy your library faithfully, anything left behind on the old phone copies over too. Cleaning first is the only way to keep it off the new one.
A note on safety and recoverability
Don't erase your old phone until the new one is fully set up and you've confirmed your photos, messages, and accounts are all there. Anything you delete during cleanup goes to Photos > Albums > Recently Deleted and stays recoverable for about 30 days, so a wrong tap isn't permanent. Keep at least one current backup (iCloud or Mac) until you're certain the migration succeeded.
FAQ
Should I delete photos before or after transferring to my new iPhone?
Before. If you transfer first, every duplicate and oversized video copies to the new phone and gets backed up again. Cleaning the old phone first means less to copy, a faster transfer, and a tidy fresh start.
Will cleaning the old phone affect the new one if I use iCloud Photos?
Yes, intentionally. With iCloud Photos turned on, your library is shared, so deletions sync everywhere. That's exactly what you want here: clean once and both phones reflect it. Just confirm everything looks right before the 30-day Recently Deleted window closes.
Do I still need a backup if I use Quick Start?
Keep one anyway. Quick Start migrates data directly, but a current iCloud or Mac backup is your fallback if the transfer is interrupted or something doesn't come across. Don't erase the old device until you've verified the new one.
When you're ready to clean fast, Cleanor for iPhone sorts your library by size and duplicates so you can free up iPhone space before the move, all on-device and private.