There are just over 600,000 letters all told, more or less the same as the number of males who came out of Egypt, indicating that everyone is indispensable to the people of Israel; a Torah which lacks even one letter is not kosher, and neither is the Jewish people complete if any of its members is missing. This is a well-known idea which remains valuable even though it is hundreds of years old.
Another idea which derives from the vav of gachon is that the time to assess a human being is not merely at birth when the baby is full of promise, or at the end of life when one’s earthly chapter has come to an end, but in the middle, when the question a person should be asking is, “Now that I am halfway through my task, how am I doing?”
Naturally we are unable to judge when we will die, so how can we pinpoint any particular stage and call it halfway?
The answer is to divide life into three segments, youth, adulthood and old age, and regarding oneself as statistically likely to reach the 70s or 80s or more, use the stage of life beginning with one’s late 30s as the time for the middle-of-life assessment.