Not so with a dcvs. When you check out some code, you get a copy of the repository, with all of the changes. In Mercurial, copies are super cheap, so you are encourages to then create multiple copies of the repo. For instance when you start working on a feature, that feature should get a clone of the repo. How do you version control your local copy in svn? You don’t. You work and then submit when you’re done or whatever. With mercurial you can keep copies of what you are doing. Explore new ideas. When you are done, you can push and pull changes between each repo you made to put together your change, then push all your code back up to a main repo, or whatever. Working this way is great with patches and kepts the changes and history very clean. I dig it.