balibones - 1:28 pm on May 27, 2011 (gmt 0)
I agree with underglass.
You should also make sure the date on the page changes (If you have one. Personally I'd remove it) as well as the last updated date in your header and feed (if you use them).
Micheal Gray has written about this several times. What you should go search for is "living URLs" or "evergreen content".
Here's one of Graywolf's posts on it: