^^^ I do the same as AJ and H20. I learned from Maya, Appleman, and some Penn State profs to not go hog-wild. They advised to take it a step at a time, so you don't eliminate too much leaf surface for photosynthesis/growth reasons. I usually take off 1 or 2 of the lowest limbs in the early years, careful to leave other limbs above for growth. As I was told, you can always remove the lowest limbs later, once the trees are established and a bit bigger.
I try to end up with our lowest limbs at or above 6 ft. Your needs may differ.