As a general rule, I have been told 300-500 miles should be the life expectancy of a pair of running shoes. I had just passed 300 miles in my Brooks Ghost, so I stopped by Charm City Run. My buddy Tom hooked me up with a pair of the new Under Armour Speedform Gemini 2 Record - a shoe that tracks distance (and more), untethered - and asked me to try them out.