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 and restocks. What is compared: price, original price, discount, on-sale flag, payment-method price, stock (inStock, sizesInStock), sizes, per-size variant price and availability, colour siblings, title, brand, seller, shipping and badges. What is excluded by default (still returned in the row, never a change): scrape timestamps, image and video links, and instalment text and plans; size and variant lists are compared regardless of the order the store returns them. Ratings and reviews never count. 'Changes to watch' narrows this to price and stock only. Turn on 'Emit unchanged' or 'Emit expired' only when you also want those rows returned (and billed). State is kept separately for each search and filter setup; use State key to name or deliberately share a monitoring campaign. To continue one specific interrupted run instead, use Resume from a previous run above.