Quote - I have a very simple and effective approach, my runtime is always below 2GB that is the size of driver E:.
I don't use all what I have, I keep only in disk what I use. Time to time I add something new and what is obsolete or don't use it anymore goes to a CD, I have more than a hundred of CDs (zipped).
Is very easy to administrate 2GB and a full backup of my actual Poser fits in only two zipped CDs (in one all the textures and in the other all the runtime).
If very good to have a small partition, when you have no space to put something new it means that you have a lot of obsolete things to saved for making room for the new.

That's very good in theory, and probably works great for disciplined folks. I even tried to do that once myself, but kept saying "oh, I'll use that tomorrow".

I had a sheer terror moment once myself, backed stuff up on a DVD-RW instead of a plain DVD, and wiped it by mistake! luckily, I redownloaded most of it...