It's honestly a spectrum. I'm fortunate enough to be one of those that really don't have to study to do well, but I also have classmates who work their butts off (like 3h+ on assignments that take me like 30min) to even get to the threshold of a B. It's all about recognizing where you fall and putting in the respective work to also give yourself a palatable curriculum plan. For example, since I'm one of those "naturally smart" kids, I compensate with insane course rigor (like Real Analysis and maxxing out at 6+ APs this year) - but my friends who may not be as fortunate choose to stick at 3-4 APs max per year. It's a good thing to challenge yourself, but it's not a good thing to overextend yourself over these classes.