Average Fetch Time May be Affected by Groups of Slower Pages
If Google is spending more time crawling a particular group of slow pages then it may make the average fetch time and crawled data look worse.
Rendered Page Resources Are Included in Google’s Crawl Rate
The resources that Google fetches when they render a page are included in Google’s crawling budget and reported in the Crawl Stats data in Search Console.
Sites With Slow Response Pages are Crawled Less
If Google can’t recrawl pages quickly enough due to poor page response times then they won’t recrawl pages as often as they would like to.
Search Console Crawl Stats Include URLs Fetched by Other Google Products
Google’s crawl stats in Search Console are an accurate reflections of Google’s own crawling logs, but they include URLs fetched from other Google services which use the same infrastructure as Googlebot, including Google Ads landing page checks and product search crawling.
Upper Limit For Recrawling Pages is Six Months
Google tends to recrawl pages at least once every six months as an upper limit.
Google Adjusts Crawl Rate Over Time Based on a Site’s Performance and Content
When determining the crawl rate for a website, Google will try to adjust it automatically over time, taking into account how fast the site returns results and how much content there is to crawl.
Google Can Crawl Different Parts of a Website at Different Speeds
Google is able to detect how frequently the different sections of a site are updated and crawl them at different speeds, so that the frequently changing pages are crawled more regularly.
Fluctuations in Googlebot’s Download Time Caused by Changes In Server Speed, Page Size and Page Complexity
If GSC is showing that Googlebot is spending more time downloading pages on a site, the pages may have become large, more complicated or it could mean that the server is slower.
There is No Way to Reduce Google’s Crawl Rate of Certain Pages
You can’t instruct Google to crawl pages less frequently, but instead you can put more emphasis on more important pages to be crawled by using internal linking.