Toothbrushes eventually wear out and need to be replaced. Many dentists recommend that adults and children change their toothbrushes every three months or so. If you are using an electric toothbrush, read the directions that come with it because you may not need to change toothbrush heads as frequently as that. Patients with gum disease are encouraged to change their toothbrushes every four to six weeks to keep bacteria at bay. After brushing, rinse your toothbrush with hot water to kill germs and clean the bristles. And, if you’ve been sick, be sure to change your toothbrush as soon as you can.