Using multilevel models, this study examined whether students with varying academic ability benefit equally from perseverance and intellectual curiosity in terms of academic achievement. In addressing this question two perspectives were applied: a trait perspective, focusing on differences between students, and a state perspective, focusing on differences within students across semesters. By means of an online questionnaire, undergraduate students (N = 2272) were asked to rate themselves on perseverance and intellectual curiosity at the beginning of five consecutive semesters. Results indicate that academic ability but also personal qualities have to be taken into account to explain the differences between students in academic achievement. In particular perseverance was found to be important in explaining differences both between students and within students across semesters. Also, individual students fluctuate quite substantially in their reported perseverance and intellectual curiosity from semester to semester.