Turn this on for daily or recurring monitoring. The first run returns every matching product as NEW. Later runs return only what changed (NEW, UPDATED, REAPPEARED), and a product whose listing data did not change is neither read again nor charged. What is compared: price, was-price, savings and sale end, unit price, title, brand, model, ids, in-stock, pickup and parcel availability, free shipping, packaging, badges, highlights, specifications, categories, collections and promotions. What is excluded by default (still returned in the row, never a change): scrape time, the product's rank on the page, the store nearest the connection, per-delivery-method availability detail, and the counters stock units, review count and average rating (they tick between two reads of an unchanged product; turn on 'Count stock unit changes' to compare the stock counter). Lists whose order carries no meaning (badges, collections, categories, promotions) are compared regardless of order. 'Changes to watch' narrows the comparison to price, sale and availability only. The state is kept per scope: search terms, links and the detail and review settings, so two different scopes never mix; caps, proxy and the incremental controls themselves never start a new baseline. Use State key to name or deliberately share a campaign. A run that ends early (time limit, abort, server move) remembers the rows it already returned, so the next run does not return them again; after a run is killed without notice the last few rows can return once, and Resume closes that gap. To continue one specific interrupted run instead, use Resume from a previous run above.