I just don't understand this. I've used Debian and Ubuntu for many years, and I've never had to reinstall a single installation for any reason. I use packages whenever possible, and when installing unpackaged software, I use checkinstall to make a package from it. When I move to a new system or disk, I rsync the filesystem over and boot from the new disk. There is no accumulated cruft; or if there is, it's limited to e.g. tiny config files in /etc from older package versions, which aren't a problem or even noticeable.

The closest to cruft is hidden directories in my homedir from software I don't use anymore. That isn't a problem either: they don't take up much space, and it's easy to manually delete them if I ever feel like it. If not, they are compressed and deduplicated by backup software, and they're hidden by default, so who cares?