Brakes can squeak for a variety of reasons, but continuous squeal & grinding sounds may mean it’s time for new brake pads or shoes. Worn brakes can even mean longer stopping distances and difficulty stopping in a emergency situation. Rotors & drums that are too thin May even become stressed and break.
Brakes rarely fail suddenly. They deteriorate slowly with wear. Brake life depends on many factors such as terrain, city vs. country travel, driving style, even climate. Brakes are a normal wear and tear item for any car, with heavy emphasis on the wear. Eventually your brake system parts are going to need replacement for performance & safety reasons.
Brakes are important and regular service is advised. You should inspect brakes every 5,000 miles for basic pad wear and replace disc pads when there is 2 mm or ⅛ of a inch of friction material remaining on the backing plate. Do not let brake pads wear down farther than this or you may suffer brake fade and brake failure making your next brake repair costly.