I used to keep a log book on the airplane not on myself...I'd record the temp, wind speed and direction, sky....then the flight number ie 1, 2 3 ,etc....what I did during the flight.
I was surprised how much we over estimate the number of flights....My 4 Star 60 had over 34 hrs of flight time....which doesn't seem like much until you realize this was done at 10 to 15 minute flights