| | Dental Health | Cavities What does it mean if your on period 3 or more days? If your period lasts for 3 or more days, it is considered normal. The average length of a period is 28 days, but can range from 21 to 35 days. Cavities - Related Articles Is Cannabis a Potential Lung Cancer Treatment? Proper Storing of Lithium Batteries What causes sleep apnea? Use of Birth Control Pills for Painful Menstruation Winter Nutrition Tips Migraine Relief With No Caffeine Who was lady Jane greys mother?