Most sleep clinicians and scientists will agree that if a patient with sleep apnoea is symptomatic and has an apnoea/hypopnea index (AHI) of more than 15 events per hour, he or she deserves treatment. However, there is a large group of patients with mild and moderate sleep apnoea who are asymptomatic. For these individuals, the decision of when to treat is a grey area, and current guidelines leave clinicians wondering what to do.