4. Replace your brush periodically
If you brush your teeth as often as you should, you will realize that your brush becomes more and more worn and you need to buy a new one every once in a while. This is important because your brush needs to be in good condition so it does its job. After a while, the bristles become bent and lose their rigidity, and that will cause your brush to be less efficient at removing food and bacteria from your teeth.
Also, your brush will grow its own population of bacteria after a while, because the bacteria that stay in your brush after you use it will grow in the moist environment and multiplicate. There are special brushes that are antibacterial, but even those you need to change every once in a while. Make sure your brush is in good condition and replace it every two or three months.