Do you have recommendations on how many AP courses a student should have at time of applying for colleges?
Rather than focusing on number of Advanced Placement (AP) courses, I would instead concentrate on curriculum choices that make sense for your child. The expectations at the most selective colleges in the country are that the student will go to the highest level available in all five major subject areas (math, science, history/social science, English and foreign language). This can and often does mean taking AP courses in all five subjects by the time the student is a senior, though not all high schools will offer AP classes in all subject areas. If they are not offered, the student will not be penalized for not taking them (you can’t take what isn’t available!). Those colleges also expect to see excellent performance in those, and all, courses. As colleges get less selective, the expectations in terms of curriculum rigor get slightly lower, and many of the schools in this country don’t expect to see any AP classes at all.
Don’t Forget the Other Parts of Your Application
All of that said, a student doesn’t become a much more interesting or competitive candidate just because he or she has many AP courses in his or her curriculum. Engagement and interest in the material are equally important, as are all of the other elements of the application, including involvement outside the classroom, test scores, teacher recommendations and essays. In my time as an admissions officer at Penn, I never counted up the number of AP classes a student had taken and brought that fact up in selection committee as a selling point. Instead I looked for evidence of an interested and interesting student in all of the elements noted above.
(Note: Some large public university systems, like the University of California, do reward students for loading up on honors and AP courses. My main advice remains the same though. Students are not more competitive simply because they take these more advanced courses. They also need to do well in them!)