Keep an eye on your mobility. With BVG MeinTag you have your automatic mobility log book with you all the time. With the calendar you can review where you've been and how you got there. With the map you get an overview over every track. Through your personal statistics you find out which transport means were the fastest for you and which you used most often.
Compare yourself to other users and see how green, how fast and how far you travel compared to the others.