While it’s tempting to keep your Brita filters in use for as long as possible to save money, leaving them unchanged may actually leave you with worse water overall. Each filter is only capable of holding so much material, and they lose their effectiveness once they reach at point. Once the filters are filled with trace minerals and bacteria, there’s nowhere else for them to go, and they might start filtering back into the pitcher. The filters can also act as a breeding space for bacteria that then contaminates the pitcher.  For this reason, it’s essential to follow the replacement instructions for your specific Brita filter style, which will usually have you changing out the filter every two or six months, depending on the style. Many pitchers make the process easy with a SmartLight indicator or built-in LCD screen that counts down from your last filter change so you know when you’re due for a new one.