If your internal drive fails, you can swap for the external drive and most likely it'll boot like normal if you use the same connections. If not, just go into the BIOS and select the former external drive to boot first.
"...swap for the external drive..." That involves dragging my computer hutch away from the wall (a two-person job) so I can go around behind it and disconnect about a dozen cables, then dragging the tower case out the front of the cabinet, disassembling the case (tools required) and then removing the SSD (more tools). Then reverse the procedure when I am done restoring the system.
It just might
be easier to hold the F12 key after pressing the power button.
Can I partition the destination disk when making the original clone before
the cloning operation? I'm guessing not, the cloning operation probably erases the partitions the moment it begins. But after the clone is complete, then I can partition the cloned disk to a size that my SSD will be happy with should I need to restore it. Is that how it works?
I would only be recreating the clone a few times a year, generally after significant changes to the system drive (the SSD). Like major Windows updates, or software updates or additions that require a lot of configuration. For example, it takes me hours to get Excel and Word looking and working just the way I like them. And, sometimes, Windows just goes tits-up, like mine did when it would no longer index and search the hard drives. My research into that told me that it is not an uncommon problem, and that nobody
has found a general solution. What worked for one person didn't work for anyone else type of thing.
And, SSDs are known to just cease working with no warning, irrecoverable. I want to be prepared for that [inevitable?] eventuality.
is very well backed up, with backups of the backups in the external USB docks, and then backups of those
backups kept off premises. Redundant copies of the really important data are kept on the hard drives that have the multiple backups.