You're driving down the road and you hear a squealing noise from your car. You apply the brakes and it goes away or changes pitch. This is a great time to come in for a brake inspection.
As pictured above, this is an issue of hearing squealing noise and trying very hard to ignore it. However, as always, the worn out parts win the challenge. In this case, the brake pads wore completely out and cut the braking part of the rotor from the part of it that bolts to the wheel. Not only did this add a lot of expense to the repair, but it was very dangerous.
So, when you car is talking to you, stop and take note. Then bring it into your repair shop and let them take a look at it. If it is something you can ignore, great! If it is something that needs attention, be safe, and get it repaired to save yourself time (from sitting on the road waiting for a tow truck) and money (from having to replace more parts).
Drive Safe! :D