Save yourself time and money.
It can be very frustrating to discover you're further from your goal than you thought. Avoid an unpleasant surprise and track your degree diligently with the many tools available to you. Know the courses needed to complete your degree by regularly conducting an informal degree audit, and by meeting with your advisor regularly to officially chart your course.
You'll also help yourself stay on track by knowing the academic calendar - a missed deadline can be costly!