More than likely you do. The only exception is if it only squeals in damp or rainy weather as this is a common occurrence. The best course of action is to have your brakes inspected or inspect them yourself. If your brakes have just started squealing, then you may be able to just replace the brake pads themselves. I recommend replacing the rotors at the same time. If you replace the rotors at the same time, it will prolong the life of the brakes and help prevent unwanted noise caused by two uneven surfaces. The days of having your rotors turned are in the past since the price of rotors have come way down.