What could be more absurd or ridiculous than to give advice on aging?
I have never paid attention to people giving advice on aging. Why should you?
To get to 100 years old, your heart must beat 3 billion times. That is a lot, more than any living human can understand or explain. Thinking someone knows how to get to 3 billion heartbeats is absurd.
My advice is about making old age comfortable. In my early thirties I learned how to practice zazen, which is sitting meditation with an empty mind. I have continued to do this practice ever since, daily (weekdays) for a half an hour. Now in my old age I can sit comfortably doing nothing for hours or days on end, comfortably.
That is a very helpful practice when your energy is low and nearly all your close friends are dead. I’m glad I can do it. I have led a very energetic life; now is the time for serenity.
I am not advocating for any specific form of meditation nor for any of the ideas, like enlightenment, that presumably are attendant. Most rewards for meditation, such as enlightenment, seem overrated. But being serene in old age is a great payoff.