I always hear people speak of young horses, as far as experience and training goes. What do you consider young? I know that age really does not matter as much as how much experience goes. You could have a 10 year old with little or no experience or a 5 year old that has 1000's of miles on him. What I am speaking of is at what age is a horse considered "sensible" and "thoughtful?" When does intelligence kick in and the baby recead?