What to look for when buying a used 116519 daytona?

[nbzxdk]

Hello everyone, new guy here!

Considering buying a used 116519 WG with leather strap from Sant Blanc. I am aware that it is a reputable shop though overpriced. The main reason that I am planing to buy from them is because they have the exact watch that I want (at least according to its description online). Asking price is 21K but has not negotiated with them yet.

Currently I own three watches: 1) Yacht-master 116622 grey dial; 2) Blancpain Fiftyfathom Bathyscaphe Chronograph; 3) Panerai 1321. All of them were bought new from local ADs. So I must admit that my experience with used high-end watches, especially used rolex, are very limited to none.

Online transaction is not a problem for me--planning to use a credit card to do the purchase via Sant Blanc's ebay or Chrono24 link. I know I may end up paying more but it gives me a peace of mind in case any dispute occurs. My question is about what I need to look for when I receive the watch, e.g., condition of the watch, etc. After all, this would be my first major purchase online.

Looking forward to hearing your advice & thanks in advance!