I found this video on YouTube and thought I would pass it along. It goes over some good reasons to perform regular maintenance on your garage door! One big thing to notice are the two different types of counter-balancing springs.
The two types of springs are extension and torsion.
Torsion Springs are the most common on newer garage doors. The work by twisting up and twisting down. They are wound up with the door in the closed position and then locked onto the torsion bar. As the door goes up, the springs unwind- providing a counter-balance to the wieght of the garage door.
Extension springs are more common on smaller, older garage doors. Note: It is very important if you have this type of springs to make sure there are safety cables present. If not, there is nothing to stop them from flying around the garage WHEN they break. Safety cables are an additional set of cables that attach at the back of the tracks (back-hang, from celing to tracks) and passing through the length of the spring to attach on the front of the tracks or wall. This prevents the extension spring from launching around the garage when it breaks! Extension springs work by stretching out as the door closes, allowing the garage door to be light enough on the way back up.