It can depend on several things. Years ago, when I was a proffesional musician,(like, before I understood the importance of living indoors and eating) I and my band joined the local Musicians brotherhood. I won't say what area of the states. I soon found out that the only benefit to belonging was paying dues! If you don't pay when due, you are suspended and cannot be reinstated until you pay up, sometimes with a fine! The other benefit to belonging was that the local dictated where you could play and where you couldn't according to their nightclub black list. It was kind of like being between a rock and a hard place. If you have not already learned, club owners are a devious lot who will go to great lengths to screw musicians every chance they get so, you either take your chances with the club owners or the union. The choice is yours. Of coarse things may have changed over the years but I doubt it. The only thing a union can garantee ius the right to pay dues. It's your decision.