Prabhupāda: So you have to spend two hours for Kṛṣṇa out of twenty-four. (walks for awhile and chants japa) Yes?
Devotee (1): Is there something wrong with sleeping eight hours?
Prabhupāda: Sleeping and eating, this is the material disease. Sleeping, eating, mating... So they should be reduced as much as possible.
Devotee (1): If you're still tired...
Prabhupāda: No, you can sleep till you are refreshed. Somebody's refreshed by sleeping four hours. Somebody is refreshed by sleeping ten hours.
Mālatī: But we should not sleep when we have, in place of our devotional service.
Prabhupāda: No, of course not. Devotional service is first.
Mālatī: So if we miss some sleep we should do it.
Prabhupāda: We should forego sleeping even. The real regulated life is that if sixteen rounds is not completed, then we have to forego sleeping. You should take out hours from sleeping. We should be... The main thing is that we should always be careful that... We are going, we have taken up a very responsible task, Kṛṣṇa consciousness. So we should be very much careful in discharging the duty. The devotee should be so much careful that he'll always see "Whether this moment is spoiled or utilized?" Avyartha-kālatvam (Cc. Madhya 23.18-19). Avyartha-kālatvam, that "My time may not be wasted." He should be so careful, "Whether my time is being wasted?" and time wasted, the time we engage for our bodily necessities, that is wasted. Generally, conditioned souls, they are simply wasting their time. Only the period which we have engaged in Kṛṣṇa consciousness, that is utilized. So we should be very much careful whether time is being wasted or being utilized.