It should be replaced once in one or two months.
Under normal circumstances, 2-3 months of toothbrush can still fight, the effect of removing plaque is not inferior to the new toothbrush, but if you use it improperly, the toothbrush may be very fast. The ideal cleaning ability is lost, and the soft toothbrush hair is more difficult to clean the food residue in the teeth.
Moreover, after the toothbrush head is deformed, people will habitually use more force to brush their teeth, and vigorous brushing can easily scratch the gums and damage the tissue. In addition, bacteria that are used for a long time are prone to bacteria, so it is generally recommended that the toothbrush be replaced for up to three months.
Need to be reminded that the replacement of the toothbrush for three months is the deadline. If the method of using the toothbrush is not proper, or if it is used especially hard, then the replacement frequency of the toothbrush should be higher. That is to say, the replacement of the toothbrush depends on the actual situation, the deformation of the toothbrush and the frequency of brushing, etc. It is generally recommended that you observe the bristles to determine whether the toothbrush needs to be replaced.