What price tracking can and cannot tell you

Reliable tracking depends on product identity, not only a page URL. Record the exact variant, seller, condition, currency, delivery cost and stock state; otherwise a seller switch or unavailable offer can look like a price drop. Treat coupons and member-only prices separately because not every buyer can claim them. Missing observations should remain gaps rather than being filled with the last known price. Before acting on an alert, open the offer and verify the checkout total, warranty and return terms.