We don't post a flat price here because spring jobs vary by door weight, spring count, and whether the drums or cables need replacing alongside the spring - and on an older Mirrormont install, we sometimes find all three need attention at once. What we can tell you is that a house built in 1978 is old enough that its original spring, if it's still in there, has outlived a lot of newer installs by a decade or two, so replacement at this point isn't premature, it's overdue. For the general service-area pricing approach and what factors into a quote, see the [spring repair page for Issaquah](/garage-door-spring-repair-issaquah-wa); we'll give you a number specific to your door once we've seen it, not before.