A good way of thinking about it is that every commit is itself version-controlled, allowing unlimited edits. This even allows two people in an evolve-enabled repo to make changes to history at the same time, and Mercurial will resolve any conflicts. It makes it trivial to commit (and even share) a "WIP" commit which you can later amend/split/whatever. It's different from git where you basically can't edit history after pushing (in Mercurial this only becomes true if you push to a non-evolvution or "publishing" repo, where everything then gets squashed for public consumption).
A good way of thinking about it is that every commit is itself version-controlled, allowing unlimited edits. This even allows two people in an evolve-enabled repo to make changes to history at the same time, and Mercurial will resolve any conflicts. It makes it trivial to commit (and even share) a "WIP" commit which you can later amend/split/whatever. It's different from git where you basically can't edit history after pushing (in Mercurial this only becomes true if you push to a non-evolvution or "publishing" repo, where everything then gets squashed for public consumption).