I feel the problem with asking a watch collectors forum for advise about starting a watch business is that often (especially if the person doesn’t have years of experience) the person in question solicits free advise from collectors with many years of experience to aid their education.
They then use that free education that was often hard fought and paid for the collectors, to a) compete with same collectors to Buy vintage watches and b) then try to sell these watches to the same collectors at a profit.
If an individual has put in the hard yards themselves over many years and earned they’re often welcomed with open arms.
I’m not saying the above describes you but every few months we get someone along saying they’re going to try and be a dealer and many do fall into the bracket above. Also some practices such as offering a warranty but not actually servicing a watch prior to sale, and banking on only 1 in x crapping out before your warranty expires doesn’t endear certain types of dealers to collectors.
Of course there are many exceptions, but generally the dealers who know what they’re doing and do it well for both themselves and their customers don’t need to ask advice on a forum.