Final answer:
Experts generally suggest daily backups for critical data, with less frequent backups for less critical or static data. The 3-2-1 backup rule is a commonly recommended strategy for comprehensive data protection, including regular tests of backup restorability.
Step-by-step explanation:
Experts recommend that file backup frequency should be based on the importance of the files and how often they change. However, as a general best practice, daily backups are advisable for critical data to prevent significant data loss.
For less critical data, a weekly backup may suffice, whereas files that change infrequently might only need a monthly backup. In certain cases, annual backups might be appropriate for archived data that no longer changes.
The 3-2-1 backup rule is commonly suggested, which means having three total copies of your data, two of which are local but on different devices, and one copy off-site. To protect against data loss, it is also crucial that backups are regularly tested to ensure they can be restored.