I work at home, so my home office computer backups are critical. My main computer is a Mac and I maintain three backups:
(1) CCC (Carbon Copy Cloner). I highly recommend this software which does a daily backup of my internal drive to an external USB drive. In an emergency I can restore from that, or even boot from it.
(2) Time Machine. This is the standard MacOS hourly/daily/weekly backup of all changed files to another external USB drive. USB drives are very inexpensive these days. This is useful for retrieving old versions of files you changed if you want to revert.
Also note that neither Time Machine nor CCC will backup external volumes. In my case, my Photos library lives on an external SSD drive. Also, iCloud is not recommended for backups – it is a syncing app. And while I also use Google Photos I have the “optimized” option selected, so my full originals are not backed up there either.
(3) Backblaze. This is a backup in the cloud, that also runs continuously throughout the day. The monthly/annual fees are very reasonable and it supports unlimited backups of your Mac or PC, including all drives connected to your computer. Why have a cloud backup in addition to other backups? The other backups assume no problems at your home or office such as earthquakes (like the large one we had last week), or fires, or robberies, or broken drives. You can easily retrieve individual files or your entire drive. I’ve been using them for years now and their service has been excellent.
I unabashedly give you this referral link if you want to try the Backblaze service. If you use it, we both get a free month! https://secure.backblaze.com/r/01a6d3
Backup early, backup often. Just in case.