The 3-2-1 backup rule
The best way to store your data safely, is to follow the 3-2-1 rule. What does this mean?
a. Store your data in at least 3 different places
b. On at least 2 different media types (hard drive, digital tape, NAS, cloud)
c. On at least 1 external location.
In short, there is the original data and 2 copies, on 2 different media types (hard drive and cloud), and 1 copy is external (cloud or otherwise).
Types of backup
There are 2 types of backups: full backups and incremental backups. A full backup is a 1-to-1 copy of your data. In the case of an emergency, you can use this backup to restore your data immediately. Preferably this type of backup is made on a weekly basis. An incremental backup is a backup of all the new and changed data since the last backup was made. Of course, the first backup is a full backup, after that only incremental backups are made. This saves storage space on your backup medium.
Nowadays, both Windows and macOS create snapshots (think of this as a picture) of your internal storage, before executing a major update to the system. If you have a snapshot, you can revert your harddrive to the state it was in before the update, in a matter of seconds.
In practice
Snapshots. This type of backup is automatically made on both Windows (restore point) and macOS. Make sure your computer is up-to-date and uses the latest version of the OS, as this will have the most recent security updates and bugfixes.
Local backup. Both Windows and macOS have a backup function built in the OS, to make a backup to a local hard drive: Windows Backup and Apple Time Machine.
External backup. There are multiple options for cloud backups. Let’s talk about 3 of them: iDrive Personal, Backblaze and Carbonite. They all have different specifications, one has unlimited storage space, the other has unlimited devices per subscription, etc.
The first 2 backups, snapshots and local backups, both protect against human errors, malware or viruses. The second type of backup is useful in case of a crash and the third type of backup protects your data in the case of fire or theft. With these 3 backups you can restore your data in a relative short period of time, if needed.