I always recommend replacing them both. WHY? Springs are rated in life cycles, usually ten thousand life cycles is the norm. If one broke, the other is usually right behind it because they have been used the exact same amount of times and they are usually cheaper to replace at the same time. Ballpark where I live is one-hundred fifty to about two-hundred and five dollars for both of them. For one it is about one-hundred ten to about one-hundred sixty dollars. I would go ahead and get them both done but, that is completely up to you. 4 yrs how often do you use your garage door each day? Must be pretty often.

The old springs were not of high quality,the door company charged 285.00 all in for both springs replaced..OUCH..though same company replaced 1 in home i sold in another state for 156..

The springs cost about $12.00 each at HD. Takes about 20 minutes each to replace the springs. But...you need to know what your doing.
Did they put a safety wire through the spring?
Ron

Ron,

Those are extension springs. I think this guy has torsion. Alot different.

Post didn't specify what he had. I thought torsion springs had covers over them. Wouldn't think they(homeowner) would know how many springs were involved with a torsion setup if it was covered. Maybe he'll tell us. Hard to advise with no information.
Ron

The only torsion springs that have covers over them are the Wayne Dalton Torque Master which is a piece of junk. The only other covers you might see on the torsion spring is a cover that is a warning sleeve, even with this you can tell how many springs there are and judging by the price he payed I'll bet they are torsion. If he paid that much for extension, someone ripped him off.