The Fresher, The Better.

Google loves new pages...sorta.

[HyperGeek]

Took five sites, didn't refresh the front page to each this month.

All of them took a five to ten position dive in the SERPs.

I then updated one of the pages and then decided to simply upload a previous version of the other front pages so that the document's date on the server was recent.

Guess what?

They all got their positions back within a week.

[vitaplease]

I'm not sure cause and effect can lead to that conclusion just like that.
It would be nice if wanting to be reindexed was that simple.
But it should certainly help to keep your pages up-to-date.