Do I need to replace both garage door springs even if only one broke?

When a garage door technician recommends replacing both springs at once, it is not upselling. It is the correct call based on how springs wear. Both springs in a two-spring system were installed at the same time and have accumulated the same number of cycles since installation. When one breaks, the other is right at the same fatigue point. The cost difference between replacing one spring and replacing both at the same visit is small, because the labor to access and remove the second spring is already done when the technician is working on the first one.

Why both springs wear out at the same rate

Torsion springs have a rated cycle life, typically 10,000 cycles for standard residential springs. One cycle equals one full open-and-close sequence. If your household uses the door 4 times per day (two cars, once each way), the springs reach their 10,000-cycle limit in about 7 years. At 2 cycles per day, about 14 years.

Both springs in a two-spring system experience every single one of those cycles together. They wind and unwind in sync with every door movement. One spring does not work harder than the other on a properly balanced door. They share the load equally, which means they age equally.

When one spring fails first, it is often because of a small difference in manufacturing, in local corrosion, in the exact position of a coil stress point, or in a slightly different initial winding. These are random small variations, not a systematic difference between the two springs. The surviving spring is not significantly younger or less fatigued. In fact, once the broken spring is removed, the surviving spring will experience extra stress if it is left alone: with only one spring, any remaining use of the door forces the single spring to carry load it was not designed to handle alone, accelerating its failure.

The cost math

The labor cost for replacing two springs versus one spring is nearly the same, because both springs are accessed the same way and are in the same location. Here is what that looks like in real terms:

• Replacing one standard torsion spring (Denver metro, 2026): approximately $100-$200 in parts and $100-$200 in labor = $200-$400 total.
• Replacing two standard torsion springs at the same visit: approximately $150-$300 in parts (two springs) and roughly the same $100-$200 in labor = $250-$500 total.

The difference is roughly $50-$100 more for two springs versus one, because the second spring is simply an add-on part at the same service call with no significant additional labor cost. Compare that to what happens if you replace only one spring now: in 6-18 months, the second spring breaks. You pay another $200-$400 for that call, plus the inconvenience of another breakdown, another repair appointment, and the chance that the second spring breaks at the worst possible time.

In the vast majority of cases, the two-spring replacement is the better economic and practical decision.

What happens if you only replace one spring

If you decide to replace only one spring, the technician will install the new spring alongside the old surviving one. The problem is balance. The new spring and the old surviving spring are not matched in tension. A new spring delivers more torque per quarter-turn of wind than an old spring that has fatigued through 9,000+ cycles. The door will not balance correctly with mismatched springs.

An unbalanced door works against the opener on every cycle. The opener motor is designed to move a balanced door, where the springs counterbalance approximately 95-98% of the door's weight. When one spring is new and strong and the other is old and weak, the door tilts slightly to one side, the opener compensates with extra force, and the unbalanced stress accelerates wear on the opener motor, the rollers on the heavier side, and the cables.

Some homeowners also encounter a situation where the old surviving spring is a different specification than the new spring (if the previous installer used springs of different lengths or wire diameters). In that case, replacing only the broken spring with a matching part does not restore the correct balance even if both springs are the same age. The technician should verify that both springs are correctly matched to the door weight.

Extension spring systems: same logic applies

Extension springs (the long springs that run along the side tracks rather than over the door) follow the same logic. Extension spring systems typically have one spring per side, and both springs work the door on every cycle. When one side's spring breaks, the door hangs lopsided and the opener cannot move it safely.

Replacing both extension springs at the same visit is the correct approach for the same reason: same age, same cycle count, nearly the same labor cost. On extension spring systems, also check the safety cables at the same time. Safety cables run through the center of each extension spring and contain the broken spring if it snaps. If the safety cables are worn, frayed, or missing, replace those as well, because a broken extension spring without a safety cable can fly across the garage at significant speed and cause injury or damage.

What to ask your technician

If a technician recommends replacing only one spring, ask specifically why. There are a few legitimate exceptions: if the broken spring is significantly newer than the surviving spring (someone replaced only one spring recently for budget reasons), or if the springs are very early in their cycle life (a 2-year-old spring on a low-use door). If neither of those applies and both springs are the same age, the two-spring replacement is the correct recommendation.

It is also worth asking about high-cycle springs when you are already replacing both. Standard residential torsion springs are rated for 10,000 cycles. High-cycle springs, rated for 25,000 or 50,000 cycles, are available at roughly 50-100% more cost per spring. If your door gets heavy use (6 or more cycles per day from a busy household), the high-cycle upgrade can cut your future spring replacement frequency in half or better. On a door that sees 6 cycles per day, a 25,000-cycle spring lasts about 11 years versus 4.5 years for a standard spring. The cost difference per year of service life is significantly better with the high-cycle option.

One more timing consideration: if the door is 8 years old or older and the cables have never been replaced, ask the technician to check them at the same visit. Cables typically last as long as springs under normal use. If both components are near end-of-life, replacing cables and springs at the same visit eliminates a second service call charge and ensures the whole lift system is fresh at the same time.

G Brothers serves Denver and the Front Range with honest assessments and same-day spring replacement in most cases. We offer free estimates and upfront pricing before any work begins, and we stock high-cycle spring options for homeowners who want to extend the replacement interval.