Three months is the usual guideline but many heads have “indicator” bristles that fade to about half color as a replace-now cue, and it’s smart to swap sooner after a cold or flu. If yours is fraying early, you’re probably pressing too hard - let the brush do the work, consider a “sensitive” head, and in hard water pop the head off after rinsing to dry the shaft and give a quick weekly vinegar rinse. To keep costs down, multipacks or decent third‑party compatibles are fine, and rotating between two heads lets each dry completely and can slow wear.
