In a bboy/breakdance battle..how long should each set be?

Set meaning..lets say im in a battle..and I go out and dance..then go back in..the other guy im battling dances..and ide go out again...each time Ide go out..that would be a set..should each one be like 30 secs...10 secs?? how long :) plz help im gonna enter my 1st battle soon..been bboying nearly a year.