This is something I find interesting. Where I student-taught, my school had a ten-period day, and most teachers had two 40-minute prep periods. 99% of the time, my mentor was pulled every day for one or both of his preps to cover for another teacher. Where I am a sub right now, we have six 1-hour long periods. All teachers get one prep period. I am not typically asked to cover a class during that period (which is good and bad -- it's nice to have that time to myself, but because I do not necessarily have anything to "prep," I am sometimes bored.) How often are you pulled during your prep(s)?