Guesstimating my lifetime miles

As the bio suggests, I got serious about running relatively recently, but I've been running almost my whole life. A friend of mine posted his lifetime total miles, and it got me wondering how many miles I've run, and whether I've run more miles before or since I started training more seriously.

Naturally I decided to see if I could come up with a reasonable estimate of the total number of miles I have run in my life.

I got my first Garmin in September of 2010, about 4.5 years ago. I had started building up my mileage in anticipation of my first marathon about 6 months before that. Up to that point, with the exception of a couple years when I tried my hand at half-marathons, I never ran much more than three or four miles at a time. But I was a consistent runner, logging 3 or 4 miles a day for 5 days out the the week.

So I figured I averaged 15 miles a week for the years before I got my Garmin, starting my sophomore year in high school when I joined the cross country team.

But there were some years when I didn't run much, toward the end of high school, and again when we had babies. My best recollection is that I had 7 non-running years. So since I'm now 48, that means I ran about 15 miles a week for about 21.5 years before I started keeping track of my mileage.

Here's the calculation I made:

So based on this estimate, I still have a ways to go before my logged runs surpass my unlogged runs. Assuming I continue at the rate I've been running for the past 4.5 years, it could happen as soon as a year and a half from now!