Pruning the Ports Tree

[Graham North]

Is it alright to prune the Ports tree - and still do updates later.

I am running 4.8 stable and recently did a full Ports tree update using CVSUP.   This generates several questions.
1) I took the advice of Michael Urban's book and upgraded from the "Head" of the source tree rather than from that for 4.8 - did I really want to do that?  Does it matter for a Ports only updating?
2) The tree is getting pretty big - result, lots of files.   My hard drive is not very big - it is down to a few hundred inodes (file handles) within the usr directory.   Can I prune the tree on my hard drive without compromising future updates?  If it helps, my machine is not using X only command mode so there are lots of Ports that will never be made.

Thanks for any help that can be offered.

Graham/