If you're the sort of person that likes to try out stuff from different places, including compiled binaries, non-repo packages, and other fun stuff, eventually

If you're the sort of person that likes to try out stuff from different places, including compiled binaries, non-repo packages, and other fun stuff, eventually stuff will break. A lot of desktop pieces of software have config files that keep changing. I've found that keeping your old /home around and a copy of installed packages works well enough for most situations.