What Matters Most When Evaluating a Vintage IWC Watch?

Hi everyone 

I’m relatively new to collecting IWC watches and wanted to ask a general question to learn from more experienced members here.

When you’re evaluating a vintage or pre-owned IWC piece, what do you personally consider most important first — movement condition, originality of parts, service history, or case/cosmetic condition?

I’ve seen different opinions online and I’d really like to understand how collectors here prioritize these factors in real-world decisions.

Would appreciate any insights or personal approach you follow 

Just my take.................

As for all vintage watch buys, provenance, condition, and a trusted seller are all important.

Equally important for a vintage watch is a complete set of box and papers but due to age it's often impossible to have, but always a nice bonus if available.