Excess Baggage

I have a fairly limited 'C' partition about 36 gigs. It seems that whenever I install an application or upgrade or any kind of addons, there is a significant extra amount of space taken. I figure there is about 500 megs to 800 megs added on.1. I do not use restore. I backup my drive manually.2. I check for TEMP and tmp files and delete them all.3. I check for duplicate files and delete safely the redundant one.4. I believe most of the extra stuff resides in the 'numbered installation folders'. I think they are used to repair any corrupted application. I did delete, very carefully, some of those files.Has anybody been successful in removing those hopefully unneeded files? I would like to redeem some of that extra space.Any help is appreciated.Thanks.Abe