Measuring spiritual advancement is done in many ways. One way mentioned in the Srimad Bhagavatam is that three things occur simultaneously for a devotee, “in the same way that pleasure, nourishment and relief from hunger come simultaneously and increasingly, with each bite, for a person engaged in eating.” (11.2.42) Srila Prabhupada also reportedly wrote, in a letter to a devotee who didn’t feel he was making advancement, that progress in spiritual life was like sitting in an airplane. During take-off one may look around the inside of the aircraft and see no changes, but when one looks out the window, and sees the ground hundreds or thousands of feet below, there is no doubt that he or she has moved upward. Another measure of spiritual progress is to determine how many devotees one is ‘making.’ A relevant Prabhupada citation here is this one: “Srila Bhaktivinoda Thakura has said that a Vaisnava is meritorious in proportion to the number of devotees he has created. A Vaisnava becomes superior not simply by jugglery of words but by the number of devotees he has created for the Lord. Here the word rantidevanuvartinah indicates that Rantideva’s officers, friends, relatives and subjects all became first-class Vaisnavas by his association.” (from the purport to Srimad Bhagavatam 9.21.18)