Totally agree on the 3‑month guideline. Two extra cues to swap sooner: when the tips feel scratchy on your fingertip or the outer ring starts to “mushroom,” even if the dye still looks fine. If your handle has a pressure sensor try to keep it from triggering, and replace a bit sooner after a cold or if you’ve got braces since they chew up bristles faster.
This is the same habit thread we see weekly. Use search; the routine is not special: one tool, twenty minutes, repeat. Track with a calendar or page numbers and keep moving. Don't clog it up with gear swaps and prompt shopping; pick ten and loop them. If you're tired, stop at the timer and go to bed. Thread's not a diary, so keep it tight.