There's no way to put a limit on what one may accomplish individually if the intent is an impeccable intent. Don Juan's teachings are not spiritual. I repeat this because the question has come to the surface over and over. The idea of spirituality doesn't fit with the iron discipline of a warrior. The most important thing for a shaman like don Juan is the idea of pragmatism.
Carlos CastanedaThe basic difference between an ordinary man and a warrior is that a warrior takes everything as a challenge while an ordinary man takes everything as a blessing or a curse.
Carlos CastanedaThe average man is hooked to his fellow men, while the warrior is hooked only to himself. Perhaps you are chasing rainbows. You're after the self-confidence of the average man, when you should be after the humbleness of a warrior. The difference between the two is remarkable. Self Confidence entails knowing something for sure; humbleness entails being impeccable in one's actions and feelings.
Carlos Castaneda