Throughout the Srimad-Bhagavatam, Srila Prabhupada emphasizes again and again the importance of retiring from family life around the age of fifty. He clearly gives this deadline - again and again.
In the purport to SB.3.30.14. Srila Prabhupada explains: "Family attraction is so strong that even if one is neglected by family members in his old age, he cannot give up family affection, and he remains at home just like a dog. In the Vedic way of life one has to give up family life when he is strong enough. It is advised that before getting too weak and being baffled in material activities, and before becoming diseased, one should give up family life and engage oneself completely in the service of the Lord for the remaining days of his life. It is enjoined, therefore, in the Vedic scriptures, that as soon as one passes fifty years of age, he must give up family life."
"Because a devotee rigidly follows the instructions of Narada Muni, he has no fear of old age, disease or death. Apparently a devotee may grow old, but he is not subjected to the symptoms of defeat experienced by a common man in old age. Consequently, old age does not make a devotee fearful of death, as a common man is fearful of death. A devotee knows that after death he is going back home, back to Godhead; therefore he has no fear of death. Thus instead of depressing a devotee, advanced age helps him become fearless and thus happy."
In spiritual life we have a very different attitude to old age and death. We happily embrace it, knowing that the time will come closer where we can finally get out of the material world. Krishna has been waiting for us for so long! Why not join Him as soon as He indicates that our time here is up?!
In the Mukunda-mala-stotra, verse 37, we can find a wonderful and humorous purport:
"One can see enlightenment among the elderly at pilgrimage sites in India, especially in Vrndavana. There one sees many old people visiting temples with intense devotion early in the morning. Hundreds of old people walk the circumambulation (parikrama) paths despite physical debilities. Some are bent nearly double! Someone might criticize that these people are not being provided with the Western medical treatment that could add a few years to their lives or ease their pain. But the sincere babajis and widows of Vrndavana who somehow make their way every morning to see Krishna in the temples and who call out "Jaya Radhe!" are actually fortunate and most intelligent. They are taking the krsna-rasayana, the elixir that will grant them eternal life in Krishna's spiritual abode. The Vedic shastras recommend that one drink this elixir from the beginning of life, but even if one neglects to do so earlier, one should by all means drink it during the waning days of life and thus cure the disease of repeated birth and death."
Your servant, Devaki dd