Sleep is a complex behavior; adequate sleep is essential for healthy functioning and even for survival. Poor sleep quality and insufficient sleep have been linked to increased risk for various illnesses, as well as with an increased prevalence of excessive daytime sleepiness and reduced quality of life. Daytime sleepiness can lead to dangerous outcomes associated with drowsy driving and has become an important public health issue. Routine health examinations that include questions about sleep habits, daytime sleepiness, and problems with sleep at night can help to educate people about the importance of good sleep habits. They provide a way to identify sleep disorders so that appropriate therapies can be instituted or proper referrals to a sleep specialist can be given.