Keeping up with version changes of Knoppix post-customise

Well having got through the remastering process (ok the ISO is burning as I type but ht whole process was delightfully smooth) I was wondering how people port their customisations between Knoppix releases.

I assume people script up their changes and just let it roll whenever a new Knoppix image is out? Or is there a cunning way to port the changes you've remastered between one version of Knoppix and the next?

I'm intrigued as we are potentially going to move our current RH9 based distro (which I master on a gold server on the hard drive and then image) to Knoppix/Debian so in the past we've been able to apply OS upgrades on top of customisations - a clear advantage to cutting down repeating work.