Backup your packages [2], overwrite / with the CD/DVD/USB installer, tell the installer to use the existing /home as the new installation's /home, then reinstall your backed up packages [2]. Any software you don't get from the repositories, keep on /home (git repos, JVM, etc).
This essentially makes the system files disposable, rewriteable, overwriteable, reinstallable at will, while all the custom config and personal data resides on /home. Keep /home backed up to multiple media. Makes upgrading to a new version relatively painless, and you get the benefit of a fresh install.
1. http://www.ibm.com/developerworks/linux/library/l-partplan/i...
Dist-upgrade is one of the main advantage of a lot of distribution not rolling, and it has ever worked perfectly for me ( i remember having a ubuntu wm with 9.10 upgraded without problem since 12.04. After that i didn't need it more). Also thanks to that i have not to teach to my parents how to format and reinstall an os, they just need to press a button when the os itself warns them that there is a new version ready to download.
It just that mint developers are more focused on make money spamming their ads everywhere rather that implement that basic feature.
I know now they have a Debian version, but I have no experience with dist-upgrade on Debian.