Recently, I was in a situation in which I really needed two separate copies of my Git repository. I was about to make a full clone of the repository, but I decided to see if Git had a better solution. And in fact, Git introduced the worktree feature not too long ago (as of version 2.5, released July 2015).

A worktree gives you an extra working copy of your repository, and it’s almost as easy as creating a new branch.

Source: Parallelize Development Using Git Worktrees

“Quickly Verify That the Project Works with a Clean Checkout” is a good reason, in particular. I often find that many repos require more gitignored files or other setup than I ever remembered.