This question seems to get beat to death about once a month and then arises again the next month. Here's a little question before the answer : What's your goal in going to BP? Maximum strength over time or is it more like sex, you do it as often as you can 'cuz it feels so good.
Maximum strength gains come from 2-3 intense classes per week with at least a day to recover between classes.
Otherwise you could probably get by with up to 6 moderate to low intensity classes per week without risking overuse injuries. After an initial strength gain from increased fitness, your results will quickly plateau this way though.
Lots of people go to classes not for results but because they like being there, doing the classes, meeting friends, burning calories, whatever. Nothing wrong with that.
Rex
Excuse me... May I motivate you?