You should brush minimum twice a day, one in the morning and one before going to bed.
If you belong to any of the following category you should brush more than twice a day:
1. You drink a lot of energy drink, fruit juice, seltzer, coffee, and anything that is not water.
2. You have a lot of restorations in your mouth such as fillings, crowns, bridges and any dental work that makes your brushing difficult.
3. You have a gum disease, specifically periodontitis where you have lost some bone around the teeth. You have a lot of pockets around your teeth where germs and plaque can get stuck and grown.
4. You have a dry mouth. If you have this, you should brush every time you eat anything because all the food that you eat sticks to your teeth causing cavities and inflammation.
5. You sleep your mouth open at night. Sleeping with your mouth open can cause a change in natural bacteria, leading to cavities and gingivitis.