A Practical Guide to Backing Up Your Files

Backups are the rare piece of computing advice where the consensus is settled, the tools are mature and cheap, and almost nobody follows it anyway. The reason is not laziness. It is that the advice usually arrives as a rule that sounds like infrastructure jargon, with no indication of what to actually buy or click.

So: the rule first, plainly, then the shopping list, then the afternoon.

The 3-2-1 rule, in plain terms

Keep three copies of anything you care about, on two different kinds of storage, with one of them somewhere else geographically.

The three copies include the original. So you need the file on your laptop plus two backups — not three backups.

"Two kinds of storage" means do not put both backups on two external drives from the same batch, sitting on the same shelf. Drives from one production run fail in correlated ways, and a shelf is a single accident.

"One somewhere else" is the part people skip, and it is the part that covers the scenarios that actually take people's data: fire, flood, burglary, and a burst pipe above the desk. A backup drive next to the laptop protects you from drive failure and nothing else.

What it actually costs

For a typical person with somewhere between 200 GB and 1 TB of material:

• An external drive, 2 TB: roughly $60–$80 one time. Buy at least double your current data so you have room for version history.
• Cloud backup: roughly $7–$10 a month for unlimited or near-unlimited personal backup, or a few dollars a month if you use general cloud storage and stay within a tier.

Call it about $150 in the first year and $100 a year after. That is the entire cost of never again losing a decade of photographs.

Sync is not backup

This is the single most common and most expensive misunderstanding, so it gets its own section.

A sync service keeps a folder identical across devices. If you delete a file, the deletion syncs. If ransomware encrypts your files, the encrypted versions sync. If you overwrite a document with a bad edit, the bad edit syncs. Sync faithfully propagates your mistakes, which is exactly what it is designed to do.

A backup keeps historical copies you can return to. The distinguishing question is: can I recover the version from three weeks ago? If the answer is no, it is sync, and it will not save you from the most common causes of data loss, which are human rather than mechanical.

Several sync services do offer file version history, often thirty days. That is genuinely useful and worth enabling. It is still not a substitute for a real backup with a longer retention window.

The afternoon setup

Step 1 — decide what matters (20 minutes)

You do not need to back up your operating system or your applications; both are reinstallable. What is irreplaceable is the material you made or collected: documents, photographs, video, projects, email archives, password vault exports, and configuration you would hate to rebuild.

If it lives scattered across your desktop and four random folders, consolidate it first. A backup you have to think about is one you will misconfigure.

Step 2 — local backup (30 minutes, then it runs itself)

Plug in the external drive and turn on the backup tool your operating system already includes. On macOS that is Time Machine; on Windows, File History combined with a system image. Both are perfectly adequate and neither costs anything.

Set it to run automatically. A manual backup is a backup that happens twice and then never again.

Step 3 — offsite backup (1 hour of setup, days of uploading)

Choose a cloud backup provider, install its client, point it at the same set of folders, and let it run. The first upload of several hundred gigabytes will take days on a typical home connection. That is normal and requires nothing from you beyond leaving the machine on.

Turn on encryption with a key only you hold, if the provider offers it. Write that key down on paper and put it somewhere you would find it after a house fire — a lost key means an unrecoverable backup, which is the same as no backup.

Step 4 — test the restore (15 minutes, and this is the important one)

An untested backup is a hypothesis. Pick a file, delete it, and restore it from each of your two backups. Then pick a file from a month ago and restore that version specifically.

This is where people discover the backup silently stopped running in March, or that it never included the folder they cared about most. Far better to find that now than during an actual emergency.

You do not have a backup system. You have a restore system that happens to make copies. Test the half you will one day depend on.

Keeping it honest

Put a recurring reminder in your calendar every three months. When it fires, do two things: confirm both backups ran recently, and restore one file at random. Ten minutes, four times a year.

That is the whole discipline. The setup is an afternoon; the maintenance is forty minutes a year; the alternative is explaining to yourself why the photographs are gone.