The belly dance world has different rules. Just for fun... ask a ballet dancer, jazz dancer, or modern dancer that question. Doing a student night is great and is a wonderful outlet for students learning to perform.... but dancing professional.... is another story. I aske this question to a woman whom directs a very famous ballet company in S.F and show looked at me with not a question in her heart and said "at least 10 years"... and that was with ballet training (taking 4/5 classesa a week).

I think this totally depends on the dancer. As long as you have a good grasp on movement and music interpretation you could essentially dance professionally. However, I think you should also be able to represent the dance respectfully as well as being poised, confident and gracious. All these things are important as a "professional" dancer. For me, I've been dancing four years now and am just now feeling like I have the ability to entertain well with all the aspects mentioned above. It may be much shorter or longer depending on your own knowledge and experience.