When does Google update the cached page?

Googlebot visits...

[guezo2]

Googlebot visits my site regularly but the cached page given by Google isn't updated. My homepage is updated every couple of days, and Googlebot indexes it once a week (or more). But the date of the cached page of my homepage is July, 7th!
Have you got the same problem?
Google used to update the cache page as soon as Googlebot had crawled it...

[steveb]

The cache date moves around a lot, especially around the update. My home page cache is jumping between July 24, July 27 and July 3.

[vitaplease]

guezo2,

I have been doing some searching around with the cache dates and spidering frequency and will post about it later if I find something conclusive.

Being spidered frequently does not mean getting a Fresh tag.
You will notice that today and yesterday no sites contain a date stamp anymore on the Google search results.
The last date stamps all carry the 28th of july as far as i can see.

As steveb says, around updates things can change.

It could also seem that recent cache dating gets calm before the deep-spidering.