Dental Association recommends: 1.changing out your toothbrush every 3 months. 2.After normal wear and tear your bristles start to get worn out creating a less effective charcoal toothbrush. 3.Clinical studies show that a worn out oral toothbrush removes less plaque than a new toothbrush. 4.Common sense practices also suggests to replace your toothbrush every 3 months. Tips of Keep You Teeth Healthy: 1.we should brush teeth twice day. 2.We should have 2 pcs toothbrush for day and night. 3.We should use hard bristle toothbrush for whitening teeth. 4.We should brush you teeth before sleeping. 5.we should changed toothbrush every two month if you want you teeth better than normal