Buying a pre-owned watch: a checklist

The seller

• Buy the seller before the watch. A dealer with a physical shop, a return period and a written authenticity guarantee is worth paying a little more for.
• On a marketplace, check the seller's history and use a payment method with buyer protection. Never pay by bank transfer to a stranger.
• A price far below the market is the seller telling you something.

Papers and numbers

• Box and papers add value, but papers are easy to fake. They should match the serial and reference numbers on the watch.
• Ask for photos of the serial and reference numbers, the movement and the case back.
• For an expensive watch, ask the brand or an independent authentication service to check it before you pay.

Condition

• Dial and hands: replacements and refinished dials cut the value of a vintage watch. Lume should match between the dial and the hands.
• Case: sharp edges and bevels mean it has not been heavily polished. Soft, rounded edges mean it has.
• Crystal and bezel: chips and scratches are cheap to fix on most watches, expensive on some.
• Bracelet: stretch between the links shows wear. Check it has enough links for your wrist, and ask for any spares.

How it runs

1. Wind it, or ask the seller to, and check it starts at once.
2. Pull the crown through every position: winding should feel smooth, setting should move the hands without slipping, and the date should change cleanly.
3. Ask for a timegrapher reading, or measure it yourself in the return period.
4. Check the date changes around midnight and every function works: chronograph, bezel, GMT hand.

Service history

A recent service with a receipt is worth a lot. Without one, budget for a full service soon after you buy: the service guide explains what it involves. Add that to the price when comparing watches.

Once it arrives

Check the lug width before you order a strap (here is how), test the water resistance before you swim with it, and set it to the second.