Conventional wisdom holds that you should replace a toothbrush you used when you were sick, lest you face extending the illness or re-infecting yourself.
Slate says after your body fights off a virus, it develops antibodies that make your odds of re-infection “very low.”
It’s a different story with bacteria, so if you get strep throat, it’s a good idea to buy a new brush. Also, it’s very possible to catch someone else’s cold if you use their toothbrush.
How often do you replace your toothbrush, and what’s the longest you’ve gone between brushes?