What I did is create a button and page called archive. All the pages that are old or that I don’t promote anymore I put in the archive and take it off the menu. It still gets mapped by the SEs and I do not loose it from being indexed. I will then use it later with new content. When the SEs bot goes thru the site it picks up the new content. I’ve found that by doing this I can get good position on keywords in less time.