True there are a high numember of them doing it, It's good for their circulation. Depending on the degree of expertise you wish to acchive determins how much class time you must spend. Traditional and Contra forms do a walk through before each dance. CDP normally is about 12 to 15 hours. Clogging, Round, and lines are constant classes because you are learning different routines to each tune.
Attire is suggested based on past experances.
However, individual club by-laws may require that their members wear a specified attire. As I understand it, one thing is a non-negotiable in many places, and that is that men wear long sleeves. The reason is for safety. If at least one person has long sleeves on, there is less chance that one's hands will slip. This is most prevalent in parts of the Midwest and South.