Dentists recommend buying a new toothbrush every three-four months, but it's hard to remember when it's time to get a new one. One simple way to remember is to just buy a new toothbrush whenever you buy toothpaste.
Image: Stocksnapper (Shutterstock).
One poster on Reddit offers up this clever tip. A full-sized toothpaste tube should last roughly three months if only one person is using it, so once it's empty, you know it's about time to get rid of the worn-down brush. If you don't trust yourself to remember this trick at the store, just stockpile some extra brushes in your bathroom and replace yours whenever you've used up the very last dollop of toothpaste.