To say that brakes are an extremely important safety consideration with your car is an understatement. There can be several braking systems on your car: normal and ABS. Today's systems are complicated in that they are operated using hydraulic pressure with the assisatce of electronic controll (ABS)within the same car. Many require special procedures and require more expertise than past systems.
Today's friction coefficients are engineered so precisely that it is imperative to use the correct brake pads for the material in the rotors. Many cars' brake pads are equipped with wear indicators that squeal when it's time for replacement. This is not something to be ignored. The squeal will go away, that is true, but to continue driving with these worn pads typically results in costly damage to your brake system. Your car's brakes should be checked annually.