The garage door opener spring is the part of the entire system that takes the torque of the door and makes it a little lighter. Without this spring, the door opener would have to work much harder to lift the garage door.
Replacement is Needed
When the garage door opener spring does not work correctly, it will need to be replaced. This brings a lot of different dangers as the spring is under great pressure. Replacing the spring is something, while needed, should only be done when specific signs of wear begin to show.
The springs, when they are closed, should be tightly coiled together. When the door is open then each of the coils will be separated and the spring straight. If there is any separation when the door is closed, or if the spring is sagging when the door is open, then the spring should be replaced. It has lost its retention and torsion ability.
Maintenance vs. Replacement
To prevent the spring from having to be replaced, it is highly recommended that a good maintenance schedule be adhered to. This should be a twice yearly cleaning and lubricating project. While this will not prevent the spring from wearing out after many years of use, it will slow down the process.