I have been tracking my cycling miles for years, and running, walking, etc. I find it motivating. I rode my highest total annual miles (9,304) in 2014 and I also turned 60. Nearly half of my miles were commuting. We had a ton of rain in 2014 that suppressed my commuting, and I easily could have topped 10,000 miles if we had nicer weather. I would like to top 10K miles in a year but I'm not obsessed with it.