I had my Conn 10M and 6M relacquered. Both of them sound as good as they did when they were new, and the lacquer makes them look like new again. Unless the lacquer is really bad, I wouldn't have it refinished, but if the lacquer is worn off and started to oxidize, then I would probably have it relacquered. The oxidizing can lead to pits in the brass....not good. As blackfrancis said, be VERY CAREFUL who you have refinish it. I've seen more bad relacquer jobs than good ones! The place that I had refinish my horns does really nice work. I had only the body refinished on my 10M and 6M. I only polished the silver keys, leaving the slight finger wear to show that the horn was in fact vintage. The Wind Works in Burton, MI refinished both of my horns. They do awesome work, although they are a little pricey. Talk to Luke Richmond (810)743-5420.