upgrades

[mike at lanline.com]

	One of the things that seems to be very vague to me is the FreeBSD
upgrade procedure.  I see that I can do a binary upgrade off the cd's, but
I'm more curious about the source upgrade procedure.  Does it do a
through job (i.e. does it remove older non-existent binaries when
upgrading)?  Or should I only upgrade like that once or twice and do a
fresh install after like the 3rd time?  Also, is it a good idea to have
one server that has CVSup running on the src and ports dir and then have
all the other servers nfs mount those directories and do all the upgrades
off of the one machines src and port dirs?

Thanks in advance.
-Mike