My impression, based on eyeballing logs for my own low traffic, unimportant sites: Google collects and uses stats on how often pages change, how often they come

My impression, based on eyeballing logs for my own low traffic, unimportant sites: Google collects and uses stats on how often pages change, how often they come up in searches, etc., and for static and/or low importance pages they scale crawling back. This frees up crawling resources to spend elsewhere, like on important, frequently updated pages, new sites, et al. I haven't looked closely in a couple of years, but the pattern used to be that new content would be crawled fairly agressively and after a while it would back off to an "appropriate" level. Back then, other search engines took a good while to begin crawling my new stuff in earnest, and once they did their crawling pattern did not seem to change much over time between a (relatively) popular changing page vs. a lonely static page.