That may totally depend upon how you use
the FreeBSD system, how secure its usage
is, etc.
The freebsd-questions list has one-or-more threads
yearly
(this year for instance ) which explain updating to a current
stable (8-stable for example) from systems
as not-current as that 6.1 one.
...
As usual, backup-first should be the procedure
to implement first. Then whatever subseq.
stuff you do I'd document on paper to make it
easier to do the v8 > v9 sometime...
...
Also keep in mind that the ports tree can
precisely NOT support building ports on
older FreeBSD versions if the ports tree
is current. That may be your most
compelling reason to upgrade.
