"Students who really need extra credit rarely seek it and students who do extra credit work rarely need it." It always seems that "A" students are far more willing to do extra credit work than a borderline student whose grade might actually go up if they completed some extra credit. Why? Motivation. "A" students are motivated to do the work and other types of students often are not willing to do more than they have to, even if it means getting a lower grade. As a result, I no longer offer extra credit.