Making use of "dead time" with Podcasts

I spend two hours, every weekday, in my car while travelling to work. I consider these two hours "dead time" because it's time spent not improving as an individual. I am not stating that I have to spend every minute of my life improving myself, but if I can't then I would at least like to enjoy myself. I could continue to listen to music, but spending 10 hours a week on the road has driven (pardon the pun) me to boredom with my music collection.

I listen to podcasts about photography while I drive to work; this has been so valuable to my growth as a photographer. I think I have at least doubled my knowledge on the subject; this is because the small anecdotes I pick up from other photographers are gems that can often be missed when reading a book or article on photography. It is easy to underestimate the power of the spoken word; especially when it is repeated. There are three types of repetition I am talking about: