There is a verse in which Srila Rupa Gosvami says, avyartha-kalatvam: [Cc. Madhya 23.18-19] a devotee should be very much careful to see whether his time is being spent unnecessarily. He should ask himself, “Am I now engaged in maya’s service or Krishna’s service?” This is a symptom of an advanced devotee. Nama-gane sada rucih: such a devotee is never tired of chanting, singing, or dancing. The word sada means “always,” and ruci means “taste.”
LFD Vol 3,Cultivating Krishna Conciousness Pg 172, 3rd paragraph.