A lot of runners (me included) are data nerds and record every runs date/time, distance, pace, weather, shoes worn, how we're feeling, temperature, elevation gain etc.

Watch the start of most race events and the first thing that people will do as they start is turn on their watches.

why? Give me 10 minutes and I could tell you the exact dates of each training program I've done since I was in University 18 years ago.

Really? I can hardly remember what the hell I was doing one day ago... I am probably just burned out though so that doesn't mean much.

I don't remember either, but I've always kept training logs. The 10 minutes are to check those!