A useful backup is a copy you can restore after the original disappears. Start with documents, photos, and work you cannot recreate.
1. Choose what matters
List the folders that contain important files. Remember files stored outside Documents, including local project folders and exports from specialist applications.
2. Keep an independent copy
Use an external drive or a backup service that keeps previous versions. A synchronized folder alone is not a complete backup: accidental changes or deletions may sync to every device.
3. Separate your copies
A practical goal is three copies, on two kinds of storage, with one copy off-site. Protect backups containing private information with encryption and keep the recovery information somewhere safe.
4. Test a restore
Create a small test file, run a backup, and restore it into a different folder. Open the restored file to confirm that it works. Repeat this check periodically and after changing your backup setup.