# Marketplace monitoring: stable listings and separate price changes

Merge snapshots by listing_id and retain change history. A price drop is an update, not a new listing. Unknown distance is pending, not 0. Exclude sold/over-budget items. Condition is a seller claim, not an inspection. Deliver candidates/questions without contacting or transacting.

Listings, locations and prices are fictional. No real platform search, user geolocation, seller contact, offer or payment occurred.