2nd hand dealer has their uses. They need to pay for security, establishment cost, staffing, fixing up faults on your watch, providing after sales warranty and finally considering the time value of money of they converting hard cash to an item that might sit there for years. Use them if you need money for urgent matters or you dont want to bother with knitty gritty of dealing with end user.
In case you consider selling directly to end user. Consider several factors such as the condition of your watch, when is the last service, any obvious dings and scratches, full box & papers. Obviously you will need to deal with low ballers, ffk buyer, buyer that request you to put on hold pending funds that might or might not come. Using chrono24 is a good benchmark and a starting point but you need to apply discount over it as selling thru chrono24 involves also transaction fee, risk that you might be scammed etc.
Just post up your watches at the preown section, if you dont get any replies within say a week or so, drop it by 5% and continue till you have a price taker or someone that will negotiate a price.
Remember that for every watch, there is a buyer (question is at what price). Go thru the price discovery process and be patient. Selling watch is like trading the share market, there are blue chips (rolex, trinity, etc etc) that you can sell without people able to arbitrage and there are untraded shares (QQ, timex etc) that when you sell, you will bring down the price by 30-40% or worst.
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