I was recently discussing dvcs with a coworker, because our office is beginning to consider switching from TFS (we're a MS shop). In the process, I got very confused because he said that although he uses Mercurial, he hadn't heard of a "branch" or "checkout" command, and these terms were unfamiliar to him. After wondering how it was possible that he didn't know about them and explaining how dvcs branches work "in place" on your local files, he was quite confused.

He explained that, similar to how TFS works, when he wants to create a "branch" he does it by cloning, so he has an entire copy of his repo. This seemed really strange to me, but the benefit, which I have to concede, is that you can look at or work on two branches simultaneously because the files are separate.

In searching this site to see if this has been asked before I saw a comment that many online resources promote this "clone to branch" methodology, to the poster's dismay. Is this actually common in the dvcs community? And what are some of the pros and cons of going this way? I would never do it since I have no need to see multiple branches at once, switching is fast, and I don't need all the clones filling up my disk.