Msg#: 4089758 posted 2:28 pm on Mar 2, 2010 (gmt 0)
A great deal would depend on what your competition is doing.
It's not automatically necessary to update just for the sake of updating, but if your competition is working actively to fine-tune their SEO you might need to respond with some tweaks of your own.
If you want to be proactive, rather than just responding to the competition, make sure you're investing steady effort into site promotion and link development. Gaining new links from quality places will have a lot of power to protect rankings already achieved.