I recall this being an issue several years ago for me but haven't had it for a long time. Virtually my entire site is now showing cache dates from early August. I know that cache dates were much more recent until a few days ago. My rankings have fallen and many pages are no longer in the index... often those added since early August.
I did a search here and find a bunch of topics on this from years ago, but can't find any recent opinions on what causes this and how to solve it. I recall in the past when I had this problem it was a "don't worry about it all will be ok in a few days" kind of thing and usually preceded a jump in rankings. I often found it coincided with getting some new good quality links. Is this still the common wisdom for this type of issue around here? Or is there something else I should be aware of?