On the first day of classes, 81% of students in an introductory biology course claimed that they would submit extra-credit work if given the opportunity. When given two chances for extra-credit work, fewer than one-fourth of students submitted one or both assignments. Students who submitted extra-credit work were more likely to attend class, attend optional help sessions, and earn higher grades than other students, even when the points earned from the extra-credit work were excluded from the calculations of grades. These results indicate that the most successful students use a variety of motivation-related behaviors to maximize their success, and the least successful students often are unwilling to expend the effort necessary to succeed.