External drives · Choosing a drive
How big should my external drive be?
Short answer: Pick a drive comfortably larger than what you plan to move — check What's Using Space and the Apps window for the biggest items — and leave headroom, because moved folders keep growing on the drive.
Big enough for everything you plan to move, with room to spare. A good rule is to look at what you'd move first — open What's Using Space and the Apps window to see the largest folders and apps — and pick a drive comfortably larger than that total, so it doesn't fill up as those folders keep growing.
Some things to factor in:
- Folders you move keep growing on the drive (photo libraries, project folders, downloads).
- If you later upgrade with Transfer Drive, the new drive needs room for everything on the current one.
- Restore Points and removed files waiting in the Recycle Vault also live on the drive, though they're small or temporary.
Storage Studio doesn't need a minimum size of its own; the only hard limit is that whatever you move must fit.