you update packages

I am experimenting with SuSE 8.0 and i get into trouble quite often. It is a price worth paying for knowledge. Anyway I need to know what is the best way to download and keep current the update packages so that whenever i have to do a fresh install I can update my system of off the hard disk instead of spending 3 or 4 hours downloading. I have already set up a partition that does not get formatted to keep files there. Thanks in advance Harry a.