I know I am probably in the minority here, but I really do not like the fact that some parents try to get their kids in this multiple times. If you get picked once, let some other small child's dream come true and keep your kid out for multiple times. There are more than a few kids who's hearts are crushed by not getting picked and there is a good chance they will never be there again...or will be back when they are too old to want to.
Our boys did not get picked twice and then were both picked on the third time. Knowing the dissapointment first hand, we told them that in the future, we would let some other little boy or girl have a better chance.
I have read on this forum of people going 5+ times. Not sure what that says about their values.