The biggest question I get is always "Where is the best place to buy a used Rolex watch?"  This is difficult because there are so many scammers on the internet and the Rolex is probably the most targeted timepiece for fakes of all kinds.  Even top sellers such as Amazon and Ebay are breeding grounds for unscrupulous sellers, trying to pawn off Rolex knockoffs or Rolexes that may have non-Rolex parts such as no-name bands which are not Rolex in any way.  Remember that Rolex takes great pride in the development of even the bands of the timepieces they make. 

The list is no specific order.  Also, I am not guaranteeing anything about what is sold on these sites.  This list is really a starting place for you to begin your research. These are the sites I look at when I am evaluating a Rolex Pre-Owned purchase.

King of the Hill Rolex Auctions
If you are a collector and you are looking for specific rare pieces then you want to first look at Sotheby's or Christies.  Both are auction houses and have low priced and high priced Rolexes for sale.  These are some of the best watches, but you are competing with collectors all over the world.  However, I find it important to look at what is sold here so that if I am looking at Pre-Owned, I know what really moves the needle in terms of value:
Sothebys
https://www.sothebys.com/en/departments/watches?locale=en 
Christies
https://onlineonly.christies.com/s/christies-watches-online/categories/387?lang=en-US 

General sites to find Rolex Deals
Although I wouldn't recommend Ebay or Amazon, these three sites are worthwhile looking at.  You might find some good deals and also some rip-off artists here.  So, definitely beware.  However, it is a great place to find how much a timepiece is selling for and where the deals are.  There are reputable dealers selling through here. 
Watch Finder
https://www.watchfinder.co.uk/Rolex/watches
The Watch Box
https://www.thewatchbox.com/watches/rolex/
Chrono 24
https://www.chrono24.com/rolex/index.htm

Specific Dealers
I like to focus on specific dealers that have been around for awhile and have a reputation to protect.  There are many of them out there that sell Rolex, but these seem to me to be the most reputable sources for Pre-Owned Rolex timepieces.  Although I haven't purchased from all of these locations, I would say this is probably the Top-Shelf of dealers and that you would be able to get both a good deal and a Genuine Rolex which is serviced properly.  Most have a good return policy in case you find something you don't like about the timepiece. 

I would love to hear from my readers to see if anyone has had a good or bad experience with any of these.  Keep in mind that every time you go to these sites, the inventory will be different.  So, you might need to visit the sites regularly if you are in search of a specific model Rolex such as a Yellow Gold Rolex Day Date with Arabic numerals.  You can also let them know what you are looking for so that they can be on the lookout for the specific timepiece you are trying to acquire:
Timeless Luxury Watches 
https://timelessluxwatches.com/watches/pre-owned/
Moyer Fine Jewlers
https://www.moyerfinejewelers.com/watches/all-watches/?gender=159&manufacturer=1771
Becker Time
https://beckertime.com/buy-used-rolex/?filter_gender=mens
Radcliffe Jewelers
https://www.radcliffejewelers.com/pre-owned-watches/?brand=rolex-pre-owned
Tourneau
https://www.tourneau.com/certified-pre-owned-watches/#prefn1=cpoBrandForFilter&prefv1=Rolex&lastOpenedTab=3
Crown and Caliber
https://www.crownandcaliber.com/collections/rolex-watches
Watches of Switzerland
https://watches-of-switzerland.co.uk/c/Pre-Owned-Watches/filter/Recipient_For-Him/

Do you agree with my list above?  Am I missing any Rolex Pre-Owned dealers that you had good experience with?  Please feel free to share your thoughts with me.  rolexchronicle@gmail.com