The ordinary aspirant, whose intuition is not sufficiently developed, should test the man he proposes to accept as his master. This will require him to watch the other closely for a period of time. In some cases a week will give the answer, in others three months will be needed. In all cases, the aspirant ought not commit himself until he has had enough evidence that he is committing himself rightly.
-- Notebooks Category 1: Overview of the Quest > Chapter 6: Student-Teacher > # 153