1. "Where did you acquire the watch, and when?"
A serious seller can answer this in a sentence — original purchase from a specific authorized dealer, acquired at a specific auction, traded from a known collector, etc. A seller who answers vaguely ("an estate sale," "private party, can’t recall") is not necessarily lying but is removing the chain-of-custody you would otherwise inspect. For pieces over USD 5,000 the answer should be specific enough to verify.
2. "Do you have the box and papers?"
Box-and-papers status meaningfully affects resale value: a full set usually sells for noticeably more than the same watch on its own. The answer also tells you something about how the watch has been kept. "Yes, full set with original retailer card" is the strongest. "Watch only" is fine but means you should ask why — if a serious piece arrived from an estate sale without papers, that is a story worth understanding.
3. "When was it last serviced, and where?"
Mechanical movements need periodic service, and the recommended interval varies by brand and movement, so check the maker’s guidance for the reference. A watch the seller cannot speak to the service history of is a watch you may need to service shortly after purchase, which is a real cost, and a bigger one for complications. Service at the brand’s authorized centre vs an independent watchmaker is a small detail buyers care about; ask which.
4. "Can you send me photos from five angles?"
The five angles: dial and bezel straight on, the crown side, a tilted side profile showing the lugs and bracelet fit, the caseback, and the clasp. A serious seller has photographed these or can shoot them in five minutes. A seller who refuses the request, or stalls, is a meaningful negative signal. There is no good reason for a real watch with documented provenance to be hard to photograph.
5. "What is the reference and serial?"
Both should be visible in the photos already, but ask anyway. Cross-check the reference against the photographed dial — a Rolex listing claiming "126610LN" with photos showing a no-date Submariner is either confused or worse. On older watches, the serial should fall in the range collectors have charted for the production year claimed. Modern Rolex serials have been randomised since around 2010, so there the check is that the serial on the watch matches the one on the warranty card.
6. "What is your return / dispute policy?"
On Chrono24 with Buyer Protection, the answer is the platform’s standard return and inspection terms; check the current window on the listing. On private sales, ask. A seller who is firm on "no returns" while asking for a wire transfer to a private account is communicating something — usually that they expect the buyer to discover a problem. Walk.
7. "Can I have the watch independently authenticated?"
A confident seller welcomes independent verification. The natural answer is yes. Check the seller’s photos against a guide yourself, then run a WatchRadar scan with the watch in your hand, at the viewing or when it arrives inside the return window. WatchRadar can’t see inside the case, so for higher-value pieces the seller should be willing to ship via escrow with a holding window for a watchmaker inspection. A seller who objects to independent verification is telling you something about the watch.
8. "Is there anything you would want me to know that I have not asked?"
The catch-all. Real sellers will use this question to flag small things — a refinished dial on a vintage piece, a previous service that replaced the crown stem, a hairline scratch that does not show in photos. Sellers with nothing to hide will use it to over-share. Sellers with something to hide will say "no, that’s everything" — which is fine if the previous seven questions were answered well, and a flag if any of them were not.