The ultimate measures of success are trial and repeat, and the buyer is the final judge. If a manufacturer of just about anything, from dishwashing detergent to automobiles, gets you to try their product, and you are satisfied and return to purchase again, that is success. Using a music example, let’s say you get a last minute call to sub on a woodwind quintet educational concert in a high school. That’s your trial. If it goes well you are a hero, even if your playing isn’t absolutely flawless. In a last minute situation the other players’ expectations are reduced, and they will cut you some slack. They’ll be happy to get through the gig without any major train wrecks! But even if you do a great job and impress the other four musicians they might not immediately call you back. There just might not be another opportunity for a while. That quintet already has a permanent member, and as long as he or she continues to do good work, it will remain his or her position. However, the chances are very good that they will recommend you to other groups, or at least relay the story of how you saved the day.