In our industry we see the some pretty severely worn out components. Noise during braking is one of the scariest in my opinion. Brakes are in fact the most important system of a motor vehicle. People sometimes think just because it still stops and that noise that it makes has been that way for as long as they remember but "It Still Stops" so they continue motoring. Braking efficiency is very important and avoiding repairs could cause an accident in an emergency situation. Having a brake inspection is cheap insurance against a potentially deadly outcome.