"The link of the pupil on probation with his Master is chiefly one of observation and perhaps occasional use of the pupil. It is not the custom of the Adepts to employ special or sensational tests, and in general, when an adult is put on probation, he is left to follow the ordinary course of his life, and the way in which the living image reproduces his response to the trials and problems of the day gives quite sufficient indication of his character and progress. When from this the Master concludes that the person will make a satisfactory disciple, he will draw him nearer and accept him. Sometimes a few weeks is sufficient to determine this; sometimes the period stretches into years."
January 1, 1970
https://en.wikiquote.org/wiki/Masters_of_Wisdom_(Theosophy)