Are you a fan of extra credit?  I am not.  I believe in giving the student the grade he or she has earned based on the regular graded assignments.  Extra credit in my opinion can really add too much cushion to a grade that is not indicative of the student's ability.  A student needs to know from the very beginning that he or she must work extremely hard to get the grade he or she wants because NO EXTRA CREDIT will be granted.  Some instructors give way too much extra credit, which can cause a student to not work to their fullest level of potential on every assignment because they know they will be allowed to do extra credit to makeup for poor grades.  In my classes you get what you have earned from working hard or not working hard on regular graded assignments.