SB 7.6.7
mugdhasya balye kaisore
kridato yati vimsatih
jaraya grasta-dehasya
yaty akalpasya vimsatih
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
In the tender age of childhood, when everyone is bewildered, one passes ten years. Similarly, in boyhood, engaged in sporting and playing, one passes another ten years. In this way, twenty years are wasted. Similarly, in old age, when one is an invalid, unable to perform even material activities, one passes another twenty years wastefully.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
Without Krsna consciousness, one wastes twenty years in childhood and boyhood and another twenty years in old age, when one cannot perform any material activities and is full of anxiety about what is to be done by his sons and grandsons and how one’s estate should be protected. Half of these years are spent in sleep. Furthermore, one wastes another thirty years sleeping at night during the rest of his life. Thus seventy out of one hundred years are wasted by a person who does not know the aim of life and how to utilize this human form.