Drop/Add is a limited-time period, typically the first week of each semester, when you may drop any registered class, get a full refund of tuition and fees (if appropriate), and have no record on your transcript that you were ever in the course. Similarly, space and prerequisites permitting, you may add courses up to a total of 18 hours. After this deadline, you can no longer add a course, and the only way out of a course is through withdrawal. Withdrawals should be conserved to cover unanticipated changes in your circumstances.