How often should you change your tooth brush?
Every three to four months.
When should you change your tooth brush?
When your brush starts to fray, it’s time to throw it away.
Why should you throw away the tooth brush when it frays?
A frayed tooth brush does not allow thorough cleaning and can result in injury to gums if used vigorously.
Source: Colgate https://www.colgate.com/en-in/oral-health/brushing-and-flossing/how-often-should-you-change-your-toothbrush-0114
Teeth Talk 