Deciding on which AP classes to take depends a lot on how many and which AP classes your high school offers. It also depends heavily on the student. Ivy Leagues and similarly selective schools expect applicants to have at least 4 to 5 Advanced classes under their belt. That's approximately two Advanced or AP classes each year since most high schools don't offer AP classes to freshmen.
Most colleges expect at least 2 to 3 of these faster paced classes by the end of senior year. But the bottom line is that every student should be taking the most rigorous classes they can take without compromising their GPA. Rigorous classes don’t only mean AP classes--rigorous classes might mean Honors Chemistry instead of regular Chemistry or Advanced Algebra instead of regular Algebra. For many students, Honors classes are the perfect demonstration of commitment to academic advancement and achievement.
The basic difference between Honors/Advanced classes and AP classes is the level of each class. Honors and Advanced classes are created by the school, usually for freshmen or sophomores. They’re usually a stepping stone towards an AP class in a similar subject. AP classes are approved by the College Board and are more challenging, college level classes.
Taking higher level classes in subjects that you like will keep the momentum going, whereas taking AP classes in subjects that are of no interest to you doesn't really benefit you in the long run and usually does more harm than good. Balancing your course load is key. Advanced classes require many hours of homework and study time. Limiting yourself to at most two to three AP courses in a year will give you freedom to spend some time on extracurriculars or just on fun and social activities during high school.
The other benefit of taking Honors, Advanced or Advanced Placement classes is the grade bump. Grade bumps are needed if students plan to apply to top tier colleges. AP classes are graded on 5.0 scale instead of a 4.0 scale, allowing students to raise their GPA over 4.0.
A 4.0 GPA just doesn't cut it anymore when you're looking at highly selective schools. Most of their applicants have a GPA well above 4.0 and high SAT/ACT test scores to match so admission decisions come down to applicants' extracurricular activities and their choice of high school classes.
In the fall of 2018, University of California, Santa Barbara received 93,000 applications for the incoming freshman class. 49% of these applicants had a GPA of 4.0 or higher. Since they only admitted approximately 18,000 students, it's safe to say that not everyone with a 4.0 GPA got in. What set these students apart from the rest of the pool? Probably their extracurricular activities, choice of classes and essays. Colleges want well rounded, diverse student populations that excel beyond academics and GPAs.
The high school years can be pretty stressful even without too many Advanced classes. SATs, volunteering/jobs and regular homework alone keep students up late at night. The best way to make sure you have a balanced year is to consider your extracurricular activities to be as important as your academic choices.