I realize that the whole "validation" question has probably been answered a lot on here, but I'm confused on how/which AP classes come into play on this subject. Because AP exams are pretty expensive, and if you have to buy 5, for example, it can be quite costly, I want to know which ones will help validate classes, if any. I have heard that some APs validate classes at the Academy but for a majority of classes you have to take an additional test during Beast. I am taking AP Chem, Calc AB, Eng Lit, Micro and Macro Econ. Which of these tests will validate classes for me if i do well on them? Which ones should I not waste my time with, if any?