Typically on my car, it was NOT the ball joints, but the inner a-arm bushings which are sleeved type....nylon-ish material against steel.....squeak every time! I found they were a "grease once a year or so" depending on mileage ya put on the car.....! Ball joints don't squeak, they just get hammered to bits......! Heims never squeak if you grease them....but that's a three day job! ))
Steve