Garage door springs typically come in pairs of two and can be found above the door. Springs are rated to last a certain length of time before they inevitably fail. When one spring goes, chances are, the other one will break soon after.
Some homeowners try to save money by replacing only the broken one, but this can lead to more costs down the road. If the second spring breaks in the following months, you’ll have to pay the fee for another service call in addition to a replacement spring.
Similar to when the headlights on your car burnout, it’s best to replace both of them together.
With that being said, there may be situations where you can get away with replacing just a single spring. If your second spring is not near the end of its rated lifespan (typically 10,000 or more cycles) and there are no visible signs of rust or damage, then it’s probably fine to leave it as is.
If you’re unsure, we recommend discussing this with the technician at time of visit. A reputable garage door repair company should provide an honest assessment on whether replacing the second spring is beneficial or not.