It makes sense to change a toothbrush when you are sick, but at what point do you toss out the old one and start using a new one to avoid re-infection?
It doesn't make sense to toss out the old when you have just started being sick, since you still have germs. But if the germs are on the toothbrush, then you are reinfecting yourself when you use it.
A friend stores her toothbrush in peroxide when she is sick. This makes sense.
So what should we do? There may be a simple answer to this that I haven't thought of.