[mcv]

Backups are of course always a good idea, but you don't need them specifically to work with git. Git is its own backup system. If you think you might do something potentially harmful, do it in a new branch. If something goes wrong, you can always throw it away.

If something has already gone wrong, and you didn't do it in a separate branch, you can still go back to a previous situation.

Rewriting history in any serious sense (beyond a local reset or rebase for stuff that hasn't been pushed to anyone else yet) is always a bad idea. History is history for a good reason.

Of course any existing commit can always be reverted; that's not rewriting history. A revert is simply a new commit.