I don't think a horse should have anyone on his/her back untill they are at LEAST 3, preferably 4. I understand that people are thinking that its just light work, it won't hurt them, but in reality it can be very damaging to the growing and changing bone structures of a young horse.

On another note, why do people feel that they have to break their horse at 2 to be competitive? Is there any reason why people HAVE to show their 3yr olds? Really, if you wait a year or two you add way more time that the horse can be comfortably competitve in the show ring. Its compleatly illogical. If you break him at two, show him 3ft when he is 5, 3'6 when he's 6, 4ft when he's 7 and 8, then you will probably have to bring him back to 3'6 when he's 9 or 10 until hes 12 or 13 when you have to move him all the way back to 3ft, and the poor horse is carrying around beginners doing 2ft or 2'6 at only 16. SAD. Whereas, if you only wait a few more years the horse can be sound and doing 3'6 or 4ft well into their teens and 3ft into their twenties even.