Driver's school licenses and instructor licenses are valid for 2 years and must be renewed before the expiration date. Schools must notify the administration in writing at least 30 days before closing, return materials within 7 days of closing, and refund all money within 30 days. To be an instructor, one must have a satisfactory license record for at least the previous 3 consecutive years, which is defined as less than 4 points. Student observers are limited to 2 at a time during behind-the-wheel instruction. Classroom instruction must include at least a 15-minute break every 90 minutes. Apprentice instructors must observe 15 hours of classroom and 4 hours of behind-the-wheel before teaching.