I also use plusses and minuses. You can help your grade significantly, however, by acquiring bonus points . Most classes will begin with a short quiz. If you get more than half the questions right, you get a point added on to your final total. Please be aware that I allow you to drop an exam grade because I strongly resent giving make-ups , not because I think you are entitled to bomb an exam and escape the consequences.
Most students experience at least one personal emergency during the semester.
When such an emergency then occurs, the student will come to me and ask for a make-up so that he or she can drop some other disappointing grade. If you, by some piece of luck, manage to get through a semester without having to skip an exam for some legitimate reason, then you may be blessed with an undeserved opportunity to get rid of some miserable grade. But I don't owe it to you. It follows that you should never skip an exam simply because you feel unprepared. And if, perchance, you decide to skip an exam despite my advice, it is an even worse idea to call me up and tell me that's what you're doing.