From time to time, your students may need to make up exams. Recall that your exam make-up policy should be clearly stated on your syllabus.  Besides allowing students to make up exams, instructors sometimes choose to let students drop their lowest exam score without having the option for a make-up exam. Another option is to replace each student's lowest exam score with the exam on the final, if that is higher.  

Be extra vigilant while your class is taking an exam. This is not the time to write lectures or work on grading or another project.  Instead, watch the class carefully and look for signs of cheating. These could include using a phone, talking to other students, using an unauthorized "cheat sheet," glancing at other students' exams, writing information on desk, and so on. Students who studied hard for an exam tend to get upset when they see other students cheating, and it's the instructor's responsibility to make sure this doesn't happen.