…”Your time is so valuable that you cannot get back your life, one day of your life or one moment of your life, by paying millions of dollars. (Srila Prabhupada lectureSB 1.2.19 New Vrindaban)
I have been thinking lately about about my life. I am 70 years old, or to break it down; 25,550 days, 613,200 hours, 36,792,000 minutes, 2,207,520.000 seconds. How much of my life have I wasted? When I wasn’t thinking about Krsna, when I was not engaged in devotional service. How many hours did I spend sleeping, or engaged in fruitive labor, intoxication or sense gratification? Really, I have wasted so much valuable time, and can never get that back.
“If such valuable time you simply waste, then just estimate it what is your loss, practically, from monetary point. One moment of your life cannot be returned by millions of dollars.
Therefore our Rūpa Gosvāmī also teaches, avyartha-kālatvam (CC Madhya 23.18). A Kṛṣṇa conscious person should see, “Whether my time has become wasted? Whether I am utilizing my time, the short duration of my life, properly?” All Kṛṣṇa conscious persons should be vigilant to see that the time is not wasted. Śrī Caitanya Mahāprabhu therefore advises, kīrtanīyaḥ sadā hariḥ.
tṛṇād api sunīcenataror api sahiṣṇunāamāninā mānadenakīrtanīyaḥ sadā hariḥ (CC Adi 17.31)
We have therefore introduced chanting Hare Kṛṣṇa twenty-four hours. I am glad to see all the devotees, they are carrying the beads, that this is nice practice. It must be. Chant Hare Kṛṣṇa, Hare Kṛṣṇa, for twenty-four hours: while working, even in sleeping. If you practice, in sleep also you will chant Hare Kṛṣṇa. That is possible. It is not impossible, it is fact.” (lecture SB 1.2.19 New Vrindaban)
..”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). 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 are engaged in Kṛṣṇa consciousness, that is utilized. So we should be very much careful whether time is being wasted or being utilized.”… (Morning walk San Francisco, 1968)
Some text pasted from: Vanipedia
The Hare Krishna Movement 