I realized that this tradition of my family and I walking around in the cold at approximately the same time each year served as a guidepost for my health, even if we didn't mean for it to function that way. My wife easily recalled what physical state I was each time we went there over the course of the past several years, though my memory was a bit foggier. In a culture based on routines that repeat annually, it is easier to notice these events as "measurements" even when they aren't intended to be. Of course, our birthdays measure how old we are, but they also, for me, measured how well I was doing health-wise. This is a bit skewed by the fact that any event that takes place in the winter for me (and probably many CFers) is more reflective of whether or not I was on antibiotics and fighting an infection at the time. Other events though, like the start of the school year and my son's birthday, gave me clear year-to-year snapshots of How Am I Doing.
I hope that these annual "mile markers" are not as relevant to me going forward, or, rather, that quantity can become the focus and quality, because it is so consistently good, can fade into the background. I am familiar with the saying "It's not the years in your life, but the life in your years that count," but 100 is a nice round number, and who among us doesn't want Willard Scott to put our face on a jar of jelly?