I am both a data nerd and like to keep fit. So a fitness tracker - in my case a Fitbit - was kind of inevitable. I have worn one for about two years, and love it. But apparently the typical duration of use is just three months. Some people tire of them - just like they tire of going to the gym. Some people like the data for a while, and return to using the devices again later. Here is an interesting article from Ross Campbell, from Gen Re's Life/Health Chief Underwriter, Research & Development about how the number of steps taken each day may affect mortality. One day it would be nice if we could use all the health data that already exists - held by our government, and on services such as fitbit - so that we could automate the process of full underwriting.