I have a revised copy of the Hanon. It has been "properly translated"; I wonder if perhaps it would make a difference in performace duration.<P>Hanon himself wrote that the exercises, played correctly and quickly, were only supposed to last an hour. I assume it's true. If your piano teacher thinks not, ask him how long he takes to play through it. I'm not yet skilled enough to play through the book at the tempi marked, so I can't give you a personal guide.