A storage plan with a backup feature, and a tool with no storage
Google One's own description puts storage first: it lets you back up your phone and manage your Google account storage, using the 15 GB that comes with a Google account, with paid plans when that runs out. The backup is the reason to fill the storage, and the storage is the product.
Sync has no storage to sell. It is the part that moves files, and the destination is something you already own — a Google Drive, Dropbox, OneDrive, Box or Amazon S3 account, or a USB drive on your desk. That difference explains almost everything else about how the two behave.
The shared allowance problem
Google's free tier is 15 GB spread across Drive, Gmail and Photos, which its own listing describes when it offers to show your storage across all three and help you free up space. In practice that means a decade of mail attachments is competing with the backup you actually care about, and the usual first experience of "storage full" is not caused by the files you were trying to protect.
Buying a bigger plan fixes it, and that is a perfectly reasonable thing to do. It is worth knowing that it is what you are buying.
One copy in one account is not two copies
The standard backup advice is more than one copy, in more than one place, and it exists because accounts fail in ways disks do not — a lockout, a policy change, a login you cannot complete on a new phone. A backup that lives only in the same account as your email inherits every one of those risks.
Sync's answer is that the destination is your choice and there can be several. The same source folder can go to Google Drive today and an external drive at the weekend, as separate tasks you re-run when you want them. Nothing in Sync's design assumes the copy lives at any particular provider.
Choosing what a task does
Each Sync task runs exactly one of five operations, chosen when you build it: Backup and Backup Sync copy one way and never delete at the destination, Restore and Restore Sync bring files back, and Full Sync reconciles both sides including deletions. Naming the operation is how you decide, deliberately, whether a deletion is allowed to travel.
A second copy has to be somewhere else
The whole point of a backup is that it fails independently of the original. A copy that lives in the same account as your email does not — one lockout, one policy change, one login you cannot complete on a new phone, and both go at once.
Sync sells no storage, so it has no reason to push you toward one destination. The same folder can go to Google Drive today and an external drive at the weekend, as separate tasks you re-run with a tap, across iPhone, iPad, Android, Mac and Windows. It costs $29.99 once if you want it permanently, and that price does not renew.
Start free with any one drive, on whichever device is in your hand right now.
