@Orpheus - that's a nice story. By the way, I have never heard of a repairman who was not a musician - not all of them ex-professionals, of course, but all of them played something at some point, at least in high school. They have to be able to play test the instrument, after all, to make sure it is good to go. Many of the top brass repair guys around the country, the ones who work on the very high quality instruments, are still playing a little bit professionally too, as free-lancers.
As far as your question about how people pick who they play with, well, one person in the group is always the leader, who takes care of the business end of the group and is the person dealing with whoever is hiring the musicians, whether it is a group that plays together all the time, or it is truly a pick-up group, and he/she hires musicians he is familiar with, or come highly recommended, if they are trying someone out for the first time. Or the employer may go through a professional contractor, who hires a pre-existing group, or puts one together. I have done a small amount of that type of contracting work, hiring a brass quintet for a church for Christmas and Easter gigs. It is alot of work, especially when the church only tells you a few weeks before, and you are scrambling to find people and having to hire people you don't know, because everyone you do is already working (usually we are hired for such holiday jobs months in advance). Wouldn't want to do that full-time, but I have done it here and there. One of the first things many young musicians will do who want to get their free-lance careers going is figure out who these big contractors are in their area, and send them their resumes, etc.
Hope that answers your question somewhat.
