I prefer the xdg variables mostly for $XDG_CACHE_HOME and $XDG_RUNTIME_DIR. Those are the kinds of things I don't want to keep having to write rules to exclude

I prefer the xdg variables mostly for $XDG_CACHE_HOME and $XDG_RUNTIME_DIR. Those are the kinds of things I don't want to keep having to write rules to exclude from my backups.