full computer backup to external hard drive time machine

Here are instructions for configuring Time Machine to backup to two different hard drives. I simply replace the failing drive with another healthy drive. When one of the drives starts to die on me, I don’t fret because I know I have another full backup on my second backup drive. Storing backup data on two different hard drives provides me with some peace of mind since I know that these drives don’t last forever. Consequently, I backup my Mac to two different hard drives as well as backing up my data to the cloud using Backblaze. So I only regard them as short term restore files for which they are very useful but they are not the only form of backup I have and I would not rely solely on TM for this purpose.Do you use Time Machine to backup your Mac? There’s an adage that goes if it’s worth backing up once, it’s worth backing up twice. Add to this the unique filing structure of TM backups which are pretty much only readable by the TM app they are pretty much unretrievable if they get damaged. TM backups can become corrupted and/or the EHD's they are stored on can simply crash. If however you regard your TM backup as a sort of archive where unique files (files that are not on your computer) or versions of files can be stored permanently for restoration at any time my experience is you may be disappointed. What with the changing nature of macOS, the move from the HFS+ to APFS filing system, formatting for external HD's the increased popularity of external SSD's etc there seems no point in maintaining a TM backup for much longer than a year.

I erase my old TM backups at each major upgrade of macOS so I never have a TM backup older that about a year. As stated back in my post #2 unless you need the old backups you could just put the old backup drive aside and start a new one.

Full computer backup to external hard drive time machine