Troubleshooting My Philips Sonicare brush heads are worn out or broken It is recommended to replace your Philips Sonicare brush head every three months of normal use (brushing twice a day) or when the blue indicator bristles wear out. Below you will find more information on why this is important. Brush heads can become less effective After 3 months of normal use, your Philips Sonicare toothbrush bristles show fatigue and brush heads can become less effective at removing plague. Mold/yeast can build up If your Sonicare toothbrush has been stored wet or has not been rinsed properly after use, mold or yeast can built up. To avoid this, we advise you to: Rinse the brush head after each use Allow the brush head to air dry Dry the handle after each use Note: For health and safety reasons, please replace your brush head immediately if you are experiencing this. Still have questions? Contact our Consumer Care Agents for further assistance or visit our support page.