Everyone backs up their data eventually — usually the day after a drive fails, a laptop is stolen, or ransomware locks their files. By then it's too late. A backup isn't a copy you make once; it's a system that runs quietly so the worst day is a minor inconvenience.
This guide explains the simple, battle-tested 3-2-1 rule and how to set it up without becoming an IT expert.
What you need
- ✓The files that matter most (photos, documents, projects).
- ✓An external drive and/or a cloud backup service.
- ✓A few minutes to automate it — a manual backup is one you'll forget.
Step-by-step
- 1
Identify what you can't afford to lose
You don't need to back up everything equally. Prioritise irreplaceable files — family photos, documents, work — over things you could re-download. Knowing what matters keeps the system simple.
- 2
Follow the 3-2-1 rule
Keep three copies of your data, on two different types of media, with one copy offsite. For example: the original on your computer, a copy on an external drive, and a copy in the cloud. It protects against drive failure, theft and disaster all at once.
- 3
Automate a local backup
Use built-in tools (Time Machine on Mac, File History on Windows) or backup software to copy to an external drive automatically. A backup you have to remember to run is a backup that won't happen.
- 4
Add an offsite/cloud copy
A local backup won't survive a fire, flood or theft that takes both devices. A cloud backup or a drive kept at another location is your 'one offsite' copy — the one that saves you from disaster.
- 5
Test that you can restore
An untested backup is just a hope. Occasionally restore a file to confirm the backup actually works and isn't silently failing. The time to discover a broken backup is not when you need it.
Examples
- A dropped laptop was shrugged off because everything lived in the cloud and on an external drive — the 3-2-1 system turned a disaster into an afternoon.
- A single external drive that also died took the 'backup' with it — proof that one copy on one device isn't a real backup.
Tips
- →Automate it — the best backup is the one that happens without you thinking about it.
- →One offsite copy (cloud or a drive elsewhere) is what survives fire, flood and theft.
- →Ransomware can encrypt connected backups too; a versioned cloud backup helps you roll back.
- →Test a restore now and then; a backup you can't restore isn't a backup.
- →Encrypt backups of sensitive files, especially cloud and portable ones.
Common mistakes
- Relying on a single copy. One drive can fail or be stolen; keep three copies across two media types.
- No offsite copy. Add a cloud or remote copy so a local disaster doesn't wipe everything.
- Manual, occasional backups. Automate it — manual backups get skipped exactly when you need them.
- Never testing restores. Restore a file periodically to confirm the backup actually works.
Conclusion
A real backup is a system, not a one-off copy: follow 3-2-1 — three copies, two media, one offsite — automate it so it runs without you, and test a restore now and then. Set it up once and a failed drive or stolen laptop becomes a shrug instead of a catastrophe.