Here are reputable places (online and in-person) to buy pre‑owned men’s watches in the United States, with a short note about what each is best for and a source you can check:

Trusted online dealers / marketplaces

• Bob’s Watches — big U.S.-based marketplace specializing in pre‑owned Rolex and other luxury brands; in‑house authentication and fast shipping. Good if you want a U.S. seller and transparent pricing. (bobswatches.com)
• Chrono24 — global marketplace listing thousands of private dealers and shops; wide selection across price ranges and brands; useful for shopping globally and comparing offers. (apps.apple.com)
• Crown & Caliber (now part of Hodinkee ecosystem) — U.S. pre‑owned specialist with inspected, serviced watches and trade‑in options; good for buyers who want a curated inventory and service history. (Hodinkee.com)
• WatchBox — focuses on authenticated pre‑owned luxury watches and offers a warranty; good for higher‑end sports and luxury models and trade‑ins. (usa.watchpro.com)
• Watchfinder (US boutique) — established pre‑owned specialist with physical boutique(s) in the U.S.; good if you prefer to inspect in person. (Watchfinder.com)

Large general marketplaces with authentication programs

• eBay (with Authenticity Guarantee) — huge selection including private sellers and dealers; eligible high‑value watches are routed through third‑party authenticators (eBay Authenticity Guarantee) before delivery. Good for deals but verify seller ratings and the authenticity coverage. (pages.eBay.com)

Auction houses (for rarer/vintage pieces)

• Sotheby’s and Christie’s — major international auction houses that regularly list collectible and vintage watches; good for rare or historically important pieces (buyer’s fees and auction dynamics apply). (apnews.com)

Local options

• Authorized retailers’ certified pre‑owned desks / boutique consignment — some authorized dealers or large jewelers offer certified pre‑owned inventory and/or trade‑ins; good when you want in‑person inspection and manufacturer‑level service. (Examples include large regional jewelers or brand boutiques.)
• Reputable local jewelers and pre‑owned watch stores — look for stores with good reviews, clear return policies, and on‑site watchmakers.
• Pawnshops / estate sales / watch fairs — can have bargains but higher risk; get independent authentication and service history before buying.

Quick buying checklist (short)

• Authentication and inspection: buy from sellers with professional authentication or third‑party checks (e.g., eBay Authenticity Guarantee, dealer certification). (pages.eBay.com)
• Return policy & warranty: prefer dealers who offer a return window and a mechanical warranty or service record. (Many specialist dealers include short warranties.) (bobswatches.com)
• Service history & condition: ask for service records, photos of movement/serials, and detailed condition notes (polishing, replaced parts).
• Reputation & reviews: check independent reviews, Better Business Bureau, and watch‑community feedback.
• Price research: compare the same model across multiple platforms (Chrono24 is helpful for market price comparison). (apps.apple.com)

If you want, I can:

• Narrow this to a short list for a particular brand (Rolex, Omega, Tudor, Seiko, etc.) or price range, or
• Pull current listings for a specific model (e.g., Rolex Submariner, Omega Speedmaster), with links and recent prices.

Which brand or budget are you looking at? (If you prefer, I can immediately pull current listings for a given model and price range.)