There are two kinds of computer users: those who back up, and those who haven’t lost anything important yet.
I say that without much sympathy, having been in the second category myself for years. What ended it was losing about eight months of work to a drive failure, not dramatically, not with warning, just a machine that wouldn’t boot one Tuesday morning and a repair shop confirming the platters were unrecoverable.
The thing about backup is that it’s tedious to set up and invisible when it works. So let’s make the setup as painless as possible.
The principle worth learning first
The widely cited guideline is the 3-2-1 rule, and it holds up well.
Three copies of anything important: your working copy plus two backups.
Two different types of storage. Not two folders on the same drive, an actual second medium.
One copy offsite. Somewhere physically separate from the original.
The reasoning becomes obvious when you consider what actually destroys data. A drive fails: a second copy on another drive saves you. A laptop is stolen with its external drive in the same bag: only the offsite copy remains. A flood, fire, or theft affecting the whole room: same conclusion.
You don’t need three copies of everything. You need three copies of the things you couldn’t recreate: documents, photographs, financial records, project work. Your installed applications can be reinstalled; your daughter’s first birthday photographs cannot.
Method one: external drive backup
The foundation, and the one everyone should have.
What it is: an external hard drive or SSD connected periodically, containing a copy of your important files or a complete system image.
The tools:
Windows offers File History, which continuously versions files in your libraries, and the older Backup and Restore utility, which creates full system images.
macOS offers Time Machine, which is genuinely excellent, set it up once, connect the drive periodically, and it handles versioning automatically with a straightforward recovery interface.
Third-party imaging software provides more control, including bootable recovery media that lets you restore an entire system to a new drive.
File backup versus system image:
A file backup copies your documents. Recovery means reinstalling Windows, reinstalling applications, then restoring files. Slower, but the backup is smaller and more flexible.
A system image copies everything, including the operating system and installed programs. Recovery restores the machine exactly as it was. Faster and more complete, but larger and less selective.
Most people are best served by a file backup for documents plus an occasional system image before major changes.
The critical discipline: disconnect the drive when not backing up.
A permanently connected external drive is vulnerable to the same threats as your internal one. Ransomware encrypts every writable drive it can reach. A power surge damages everything connected. An accidental deletion syncs across.
A drive that spends most of its time unplugged in a drawer is genuinely safer.
Method two: cloud backup
The offsite component, handled without you doing anything.
An important distinction that catches people out: cloud sync and cloud backup are different things.
Sync services mirror a folder across devices. When you delete a file, it disappears everywhere. When ransomware encrypts your files, the encrypted versions sync to the cloud. Sync is convenient; it is not, by itself, a backup.
Most sync services do offer version history and a recycle bin retaining deleted files for a period, typically 30 days. That provides meaningful protection, but only within that window and only if you notice in time.
Dedicated cloud backup services are designed differently: they back up your entire machine continuously, retain long version histories, and don’t propagate deletions immediately.
Practical considerations:
Initial upload can take days or weeks depending on your connection and data volume. This is normal.
Check the retention period. Thirty days of version history is common; some services offer a year or more.
Understand the recovery process before you need it. Downloading several hundred gigabytes over a home connection takes a long time. Some services offer physical drive shipping for large restores.
Consider encryption. Services offering zero-knowledge encryption mean the provider cannot read your files. This is more private but means losing your password means losing your data permanently, with no recovery option.
A minimal free approach: even without a paid service, syncing your most critical documents folder to any free cloud tier provides offsite protection for what matters most. It’s not comprehensive, but it’s substantially better than nothing.
Method three: a second local copy
The third leg, and the one most often skipped.
This can take several forms depending on your situation.
A second external drive, rotated with the first. Back up to drive A, store it elsewhere, a relative’s house, an office, a different building, and use drive B at home. Swap them periodically. Simple, cheap, and genuinely effective.
A network-attached storage device. A small box containing one or more drives, accessible over your home network. Multiple computers back up to it automatically, and configurations with two drives protect against a single drive failing.
Worth being clear: drive redundancy is not a backup. A NAS with mirrored drives protects against hardware failure. It does not protect against accidental deletion, ransomware, or the device itself being stolen or damaged. It’s a component of a backup strategy, not a complete one.
An old computer repurposed as a backup target. Free if you have one sitting unused.
What to actually back up
People frequently either back up too little or attempt to back up everything and abandon the effort.
Essential: documents, photographs and videos, financial records, project files, email if stored locally, and anything you’ve created.
Worth including: browser bookmarks and profiles, application settings and configuration files, saved game files, and license keys or software purchase records.
Frequently forgotten: the folders applications hide in AppData or Library, containing settings you’d miss. Email archives stored outside the main documents folder. Files on your desktop, which are technically in a user folder but psychologically feel separate.
Not necessary: the operating system and installed applications, unless you’re doing full system images. These can be reinstalled.
Frequency
Match this to how much work you’re willing to lose.
For most people, daily automatic backup of documents plus weekly connection of an external drive is a reasonable balance.
For active project work, more frequent. If you’re editing a document all day, a backup from last night still costs you a day.
The key point: automate what you can. Backups requiring manual initiation get skipped, particularly during busy periods, which is exactly when your work is most valuable.
Testing: the step everyone skips
An untested backup is a hypothesis.
Backups fail silently in a variety of ways. A drive develops errors. A service stops syncing after a credential change. A backup runs but excludes a folder you assumed was included. Files copy but are corrupted.
Test quarterly. Pick a few files, restore them from your backup, and confirm they open correctly.
Test a full recovery annually if you’re using system images. Booting from recovery media and confirming the process works is far more comfortable to discover in advance than during an actual failure.
Verify what’s actually included. Open your backup and browse it. People are frequently surprised by what isn’t there.
Building it practically
If you’re starting from nothing, do this:
Buy an external drive with at least twice your used storage capacity. Set up your operating system’s built-in backup tool to use it. Connect the drive weekly.
Enable cloud sync for your documents folder, using whatever free tier is available. Confirm it’s actually syncing.
Once those two are running, add the third copy, a second drive stored elsewhere, rotated monthly.
Test it in three months.
That’s a complete strategy. It costs very little, and it will save you from the situation I found myself in on that Tuesday morning.
The point
Backup is insurance against a low-probability, high-consequence event. Drives fail without warning. Laptops are stolen. Ransomware arrives through an ordinary-looking email. Fires happen.
None of these are likely on any given day. All of them are likely enough over a decade that the modest effort of setting up backups is straightforwardly worthwhile.
Set it up this week. Then forget about it, which is exactly what good backup lets you do.