Google does not publish a fixed schedule for algorithm updates. Core updates typically happen three to five times per year, and spam or targeted updates can happen at any time.

Google makes thousands of small algorithm changes every year, most of which are never publicly announced and go unnoticed.

The most reliable sources are Google Search Central's blog (developers.google.com/search/blog), Search Engine Journal's algorithm update history page, and Search Engine Land.

Google's goal is to provide users with the most relevant, accurate, and helpful results for every search. Algorithm updates are how Google improves its ability to do that.

Announcing every change would give spammers and manipulators a roadmap for gaming the algorithm. Google announces major updates, particularly core updates, because their broad impact means many website owners will notice ranking changes and need context.

Yes, this can happen. Core updates sometimes shift how Google assesses relative quality. A website that was previously considered strong might see rankings drop, not because it violated any guidelines, but because competitors have published better content on the same topics.