Logically speaking, it's currently Qian Feng True Immortal's turn for the rotation duty, and all the guiding tasks are completed by him. When the five-year period is over, he can rest, and other True Immortals will take shifts on duty.
However, there really aren't many guiding tasks; having one every three years is already good. After all, nearly half of the True Immortals in the Jinwu Sect are cultivated locally, and a little over half ascend from the lower realm.
Whenever a cultivator forms a Nascent Soul, there's a slight fluctuation in the Zhou Tian Immortal Mirror. Dividing a thread of divine sense to monitor it is sufficient, and there's no need to stand by all the time. Of course, one cannot be too far away, or else being caught by a supervisor or an elder for negligence would have severe consequences.
