We played a weekly contradance for years. I used to tell prospective players that endurance is more important than talent is to play a contradance. I think the most important features are the ability to play up to speed and to keep a steady beat. Medleys, along with the ability of the lead to change tunes midstream, can come along later but since an individual dance can last a long time, the ability to switch tunes and keys help rest the backup's hands so the ability is worth pursuing. I remember one dance that lasted 23 minutes AFTER I started timing it. The length of the individual dance is dependent on whether the caller has room to split a long line into a shorter line, since the usual dance continues until the original couple is back in its original position. Does this help?