How many is too many? Too many is when a student is stressed out rather than stretched out. The really important thing with AP classes is that the student become accustomed to being challenged so they don't get hit like an axe between the eyes when they go to college. The secondary benefit is, if the test score is high enough, college credits transferred. Keep your eye on college prep though rather than the credits. I remember my eldest getting a D+ in AP calc. but a 4 on the test when he was a Soph. in HS. He learned how to work hard in that class and that was the most important think he learned in all of HS.
I'll agree that it's pretty good to get things like this out of the way early.
I don't think I start collecting D+'s until my junior/senior year of college.
Granted, I think I slept through AP calculus and got the highest grade in the class, so it all depends on when you hit some sort of wall.
For me, I *think* it was differential equations that first hit me hard, but I could be wrong.
