"Every one of us completely regenerates our own skin every 7 days and every single cell in our skeleton is replaced every 7 years." This statement is from the Stanford School of Medicine online. It's actually more of a myth than fact. What's true is that "red blood cells live for about four months, while white blood cells live on average more than a year. Skin cells live about two or three weeks. Colon cells have it rough: They die off after about four days. Sperm cells have a life span of only about three days, while brain cells typically last an entire lifetime (neurons in the cerebral cortex, for example, are not replaced when they die).
"In this, and the next cycle from forty-nine to fifty-six, and the periods that follow, the physical changes bring about a mental or spiritual climax. The decline of physical prowess and vitality, forces the person to direct their attention inwards more frequently. Any problems of our personality, such as maladjustment and our repressions, will undoubtedly become more urgent in these years. This reacts upon one’s marriage and professional life alike. The problem is that we have to learn to live with ourselves in a new way. We slowly have to adapt to our new-old body, and habits of long-standing do not die easily.
This is when we take an inventory of our life. It’s a time of spiritual questioning and review of our life purpose. If we haven’t successfully understood who we are by this stage and achieved our goals, then depression, moodiness and turmoil will plague both our waking life and our dreams." [source]
If you want to find your 7 year spread to see what Tony says about it click here. He covers from 0-7 years to 77 - 84 and onward.
"To be a philosopher is not merely to have subtle thoughts, nor even to found a school, but to so love wisdom as to live according to its dictates a life of simplicity, independence, magnanimity and trust."
Henry David Thoreau