Google is Able to Display Structured Data Results as Soon as the Page Has Been Re-crawled
After configuring pages to send structured data to Google, it will be able to display the structured data results the next time it crawls and indexes that page.
Google Still Respects the Meta Robots Unavailable After Directive
Google still respects the meta robots unavailable_after directive, this is used to specify a date when a page will no longer be available. John explained that it is likely their systems will recrawl the page around the date specified in order to make sure they are not just removing pages from the index that are still available.
Google Doesn’t Crawl Any URLs From Hostname When Robots.txt Temporarily 503s
If Google encounters a 503 when crawling a robots.txt file, it will temporarily not crawl any URLs on that hostname.
Google May Crawl More Frequently if it Detects Site Structure Has Changed
If you remove a large number of URLs, causing Google to crawl a lot of 404 pages, it may take this as a signal that your site structure has changed. This may lead to Google crawling the site more frequently in order to understand the changes.
Google May Still Crawl Parts of a Site With Desktop Crawler
Even with the shift to mobile-first indexing, Google may still crawl parts of a site with the desktop crawler. John explained that this will not impact the site as long as things are working well on mobile.
Use View Source or Inspect Element to Ensure Hidden Content is Readily Accessible in the HTML
If you have content hidden behind a tab or accordion, John recommends using the view source or inspect element tool to ensure the content is in the HTML by default. Content pre-loaded on the HTML will be treated as normal content on the page, however, if it requires an interaction to load, Google will not be able to crawl or index it.
404 or 410 Status Codes Will Not Impact a Website’s Rankings
If Google identifies 404 or 410 pages on a site, it will continue to crawl these pages in case anything changes, but will begin to phase out the crawling frequency to concentrate more on the pages which return 200 status codes.
Last Modification Dates Important For Recrawling Changed Pages on Large Sites
Including last modification dates on large sites can be important for Google because it helps prioritize the crawling of a changed page which might otherwise take much longer to be recrawled.
Google Has a Separate User Agent For Crawling Sitemaps & For GSC Verification
Google has a separate user agent that fetches the sitemap file, as well as one to crawl for GSC verification. John recommends making sure you are not blocking these.