If you decide to separate your site into multiple sub-sites (maybe
based on sub-folders), then you can build a site-map for each such
sub-site, according to your own schedule. Again the same deal, each
site-map can be a site-map index with individual site-maps gzipped.

Can you give me more information on how to do this?

I have been going through my site and updating things and separating
them by quarters in individual folders.

It would make sense for me to create a site-map for that folder and
leave it. I shouldn't be touched again unless I update it in the
future as it contains data as far back as 2004.

That means that I would only want to re-crawl the stuff from the last
quarter of 2009 forward.

One of the specific questions I have is how to not re-crawl the old
folder from quarter 1 but still include it in the index file.

Myck