i use to take the time to balance my tires...now i think its a waste of time.
After about 4 laps or so, your tires go out of balance, if it be dirt, rim going out of round and so on...all i ended up getting all the time was more weight on my wheels. but man i did feel a difference for the first couple of laps, smooth. But after some time, they felt worst in comparison to when i ran no balance tires.