Not sure if this is me but... In my webmaster tools it says Google last accessed my site on the 3rd Feb, my cached version says 27th Jan. It was until yesterday 10th Feb that Google updated my cache to say the 3rd Feb. Why is the difference with webmaster and the cached version so big? or do I have a problem with my site?
This is as usual - WMT and actual cache data is always slightly off - maybe because they pull the info from different datacentres, or because they're all busy snooping around Yahoo this week
Generally Google determines the time interval between consecutive crawls based on how frequently your site is changed. It keep records. If your site is changed often it will get crawled often.
I think the googlebot can visit your site, but not update the cache. I had a site where the cache didn't get updated for about a year because the content on the page changed very little.