Git only prevents switching branches if the act of switching branches would modify the files you have uncommitted changes to. In the case of fr0sty's suggestion, the new branch cannot have any changes because it's being created from the current HEAD. But even if you're switching to a pre-existing branch, it may still work depending on what files git will need to touch.
In other words, no harm in trying the `git checkout other_branch` first, and only stashing if that fails.
As GP said, not if you're creating a new branch. There's no history in the new branch to potentially overwrite your uncommitted changes in the working tree, so nothing for it to object to.
