It will depend largely upon the disciple how long his term of probation lasts. It is true that periods of one, three, five, or seven years have been mentioned in this connection historically, but it would be quite arbitrary to hold a man to any such period, irrespective of his character, circumstances, and karma. When he is able to pass the basic requirements of the Quest in morality and loyalty, in intuition and comprehension, his term will come to an end. The ego will not hesitate to use even a pretense of spirituality in order to keep its hold over him. It will persuade him flatteringly to believe that he is better than he really is. If he falls into this trap, he will not only become ensnared in spiritual pride, but also fall into various mistakes of judgement and conduct because he will be blissfully unaware of serious defects in himself.
-- Notebooks Category 2: Overview of Practices Involved > Chapter 3: Uncertainties of Progress > # 94