think about when you were a kid (ok, maybe your age, this makes me feel old) you would buy a single, and listen to it over and over and over and over and over again.... the same song. So andy and everyone else is right, just play the top 40's, maybe throw in a few remix's to mix it up, but yea.... don't be afraid to replay songs if that's what they want.... at the end of the day, they are paying you to play what THEY want