Turn this on for daily or recurring monitoring. The first run returns every matching product as NEW. Later runs normally return only NEW, UPDATED and REAPPEARED products, which makes it a cheap way to watch price drops. What is compared: price, was-price, discount, on-sale flag, unit price, name, brand, description, specifications, options with their prices and the category path. What is excluded by default (still returned in the row, never a change): scrape timestamps, the product's rank and page, the sponsored flag, delivery and pickup texts, popularity badges, the club the page was read for, image and video links, the store's generated summary, and ratings and reviews (average rating, review count, rating breakdown, topics, summary and the review sample). Stock and availability are also excluded unless you turn on 'Count stock changes' because the store's stock answer differs between two reads of an unchanged product. Option lists are compared regardless of the order the store returns them. 'Changes to watch' narrows this to price (and stock when counted) only. Turn on 'Emit unchanged' or 'Emit expired' only when you also want those rows returned (and billed). State is kept separately for each scope and filter setup; use State key to name or deliberately share a monitoring campaign. Which products a category lists, and in what order, can follow the club the connection resolves to, so for scheduled monitoring of a capped or very large category turn on 'Read every page as one fixed club'. To continue one specific interrupted run instead, use Resume from a previous run above.