Why used a trusted seller?

[jvacc]

Hello - I will be selling my Rolex (withholding model so do not appear to be soliciting) to purchase a different Rolex (again withholding model). Confused about the best way to go about this process (want to buy used).

Its commonly said in this forum to buy the seller rather than the watch. However - there are examples in this forum of people that have purchased from a trusted seller only to discover there are MAJOR flaws with the Rolex that would have been discovered with basic checks. Sure - the trusted seller sorts out the issue when its discovered by the buyer, but most sellers will do this anyway - so what is the value add from the trusted seller?

Specifically does anyone have any info on:
- How do Trusted Sellers inspect the Rolex Watches before listing them for sale? Do they simply polish the watch and sell, or do they open the case and ensure all parts in good working order/authentic? Do they check water resistance, accuracy, functionality and accurate condition?
- What is the reassurance one receives when buying from a "Trusted Seller"?
- Should I still get the Rolex thoroughly inspected by a 3rd party or do the Trusted Sellers go through thorough checks.

Also - I am located in London, UK - but all the Trusted Sellers I have found are in the USA. I have also contacted some of the Trusted USA sellers and they seem willing to buy my watch without any inspection.

Finally - how is one meant to tell how many times a watch has been polished? The used 114270s are all polished - so its really hard to understand what kind of condition these watches are in and how much use they have had.

Just trying to understand how to properly buy a used Rolex, as I purchased my first piece via Heathrow T5 brand new - bit scary trying to buy used properly