Source: https://www.makeuseof.com/backup-files-like-a-pro-three-two-one-rule/
The best way to keep your data safe is to follow the two-decade-old 3-2-1 rule: The 3-2-1 backup rule is rather simple, though people often interpret it differently. According to the rule, you should keep three copies of your data, store them on two different types of storage, and keep at least one copy offsite. It's been around for over twenty years, and it's still the clearest backup framework because it addresses every common way people lose data.
There's also a stricter version called the 3-2-1-1-0 rule that adds an immutable copy that ransomware can't encrypt and a requirement for zero errors on restore testing. That's mostly a business concern, but it's worth knowing about.
For Windows, the simplest starting point is the built-in Windows Backup for your settings and app list, combined with a proper file backup tool for everything else. I use a multi-step process to properly back up my Windows 11 PC that covers both version history and full system images. For the versioned file backup side, Duplicati is my go-to recommendation because it's free, open-source, supports encryption, and can back up to local drives, network storage, or virtually any cloud service, including Google Drive, OneDrive, and Backblaze B2. It handles scheduling and incremental backups on its own, so once it's configured, you don't have to think about it.
Your local backup could be an external SSD or a NAS on your home network. Your offsite copy could be a cloud destination through Duplicati or a separate cloud backup service. This combination satisfies the 3-2-1 rule where your PC holds the primary copy, the external drive holds a local backup, and the cloud holds an offsite backup.
When talking about backups, smartphones are easy to overlook, but the photos and messages on your phone are often the hardest things to replace. Most people rely on Google Photos or iCloud, and that's a decent start for the offsite copy. But for a proper local backup, consider using a tool like Syncthing to sync your phone's data directly to your PC over your home network. Once those files land on your computer, they get picked up by your existing backup system and protected alongside everything else. That way, your phone data isn't living in the cloud alone.
Restoring is as important as backing up: Your backups are only as good as your last successful restore. It's tempting to set up a backup system and forget about it, but backup files can get corrupted, drives can fail silently, and scheduled jobs can stop running without warning. Every few months, pick a random file or folder from your backup and try to restore it. Open the files, make sure they're intact, and confirm your backup tool can find and retrieve them without errors.
Last modified 03 November 2026