I would agree with most of the above points. I think that by listening to the tapes multiple times you are in a sense super-reading and dipping - each pass provides you with more information.
I think that you also can use this when you want to listen to a specific area. Listening to the tapes months or even years after you start in conjunction with the book should definately help those times when you think "Do I really understand this ? Am I really doing it right......" 
I know I have "lapsed" many times and started from scratch. Each time I listen to the tapes I seem to get more of the questions right - sort of a reasurrance thing !
Fraser
