Most people find out what their backup situation is on the worst possible day. The laptop won't boot, or the phone goes into a canal, or a folder that held twelve years of photographs turns out to have been emptied some time in March and nobody noticed.
The plan below takes an evening to set up and about ten minutes a year to maintain. It is not clever. Backup schemes that are clever tend to be the ones that quietly stop working.
The rule that has not changed in decades
Keep three copies of anything you would be upset to lose. Store those copies on at least two different kinds of media or systems. Keep at least one of them somewhere else entirely. That's it — three, two, one.
Each number is answering a specific failure. Three copies covers the drive that dies without warning, which is a thing drives do. Two different systems covers the flaw that hits everything of one kind at once — a bad update, a controller failure, a cloud account you get locked out of. One copy elsewhere covers the fire, the flood, and the burglary, all of which take the laptop and the backup drive sitting next to it in the same trip.
Sync is not backup, and this catches people out
A folder that syncs to the cloud and mirrors across your devices is a wonderful thing, and it is not a backup. Its entire job is to make every copy identical as fast as possible. When you delete a file, sync faithfully deletes it everywhere. When ransomware encrypts your documents, sync faithfully uploads the encrypted versions. When a photo library gets corrupted, the corruption is on every device by dinner.
What separates a backup from a mirror is history. A real backup keeps old versions and deleted files for some window of time, so you can go back to Tuesday. Most sync services do keep a recycle bin and some version history, which is genuinely useful, but the window is often short and it is easy to blow past it without knowing. Check what yours actually retains, and treat it as a safety net rather than the plan.
The evening of setup
- Decide what matters. For most households it is photos, documents, and anything creative you made yourself. Movies you can re-download and installed apps do not need protecting. Write the list down — it is shorter than you expect.
- Turn on the automatic backup built into your operating system and point it at an external drive. Both major desktop platforms include one and both work fine. Buy a drive with at least twice the capacity of what you are backing up, plug it in, and let the first run finish overnight.
- Add an offsite copy. Either an online backup service that runs continuously in the background, or a second external drive that lives at a relative's house or in a desk drawer at work, swapped every month or two.
- Deal with phones separately. Photos are the whole game here: make sure your phone is uploading to a cloud photo service, and make sure that service is included in one of the copies above rather than being the only place they exist.
- Encrypt anything that leaves the house. Any drive you carry to another building should have full-disk encryption switched on, which is a checkbox on both platforms, and a password you have written down somewhere safe.
The offsite copy is the step people skip, and it is the one that separates an inconvenience from a catastrophe. A backup drive that lives permanently plugged into the machine it backs up is protected against exactly one failure mode: that machine's disk dying. It is not protected against theft, lightning, a burst pipe, or software that deliberately goes looking for attached drives.
The part nobody does: try restoring something
An untested backup is a belief, not a system. Twice a year, pick a file you would hate to lose, delete your working copy or rename it, and restore the original from each copy in turn. Time how long it takes. Note what you had to look up.
This exercise finds problems in a startling number of setups. The drive that has been reporting success while silently failing to include a folder you moved last year. The online service that needs an account password you no longer have. The archive format that requires software you uninstalled. The external disk that was formatted for a machine you no longer own. All of these are annoying on a Sunday afternoon and devastating on a bad day.
| Local automatic backup | Dead drive, failed upgrade, file you deleted last week |
|---|---|
| Cloud sync with version history | Bad edit, small accidental deletion, working across devices |
| Offsite copy | Fire, flood, theft, and anything that hits the whole house |
| A restore test | Every silent failure in the three rows above |
Two habits that do most of the work
First, keep your files in a small number of predictable places. Backup tools protect folders. Documents scattered across a desktop, three download directories, and a memory card in a camera bag are exactly the ones that fall outside the plan. One documents folder, one photos library, everything else disposable.
Second, put a recurring reminder in your calendar — one line, twice a year. Check the backup drive is still being written to, check the offsite copy is not from two summers ago, restore one file. Ten minutes. Every backup system that failed silently failed because nobody ever looked at it.
One more thing worth doing while you are here. Write down, on paper, where the copies are and how to get into them: which drive, which service, which password vault holds the credentials. Then tell someone you trust that the note exists. A backup only you can open is a backup that ends when you are the one having the bad day.