A scrape is a snapshot
Most scraping tools work once. You crawl, export, and move on. When you come back, you run it again and compare two spreadsheets by hand, guessing at what moved in between.
Code solved this long ago with diffs. Websites need the same thing. In Silkra, every refresh is a new version and the change log is the diff: what changed, how it affects whether pages are fetched and indexed, and what to do about it.