look at all the software you’re running and what they say about making backups.
for files that don’t change often, making a an archive (with tar) is probably good enough. But if it changes during making the archive, the backup will be inconsistent.
think about your RPO: how much data are you willing to loose in case of a crash? 1 day? 2 hours? 15min? Schedule your backups to be at least as frequent.
Don’t forget to test your backups! Otherwise you’ll only find out that the backup is unusable when you need it most…
They probably mean this: https://mycroft.ai/blog/update-from-the-ceo-part-1/