How many times a day should I brush?

We recommend at least twice a day, and ideally after each of the three meals. The most important one is brushing before bed: saliva flow drops during sleep so bacteria multiply easily, and skipping it raises the risk of cavities and gum disease. Method matters as much as frequency, so please also 1) brush for 2 to 3 minutes or more at a time, 2) use floss or an interdental brush at least once a day, and 3) have nothing but water after your evening brushing.