On a house built in the mid-1960s, the classic failure is a torsion spring that's simply outlived its wind count - you'll hear a loud bang from the garage, and the door either won't budge or drops fast when the opener tries to lift it. Older Burien garages sometimes still run a single center spring instead of the two-spring torsion setup that became standard later, which means when it goes, the door has zero counterbalance left, not half. If you see the spring split open with a visible gap in the coil, don't try to lift the door manually and don't run the opener again - a spring under that kind of tension can whip the shaft. Sagging cables or a door that's noticeably heavier on one side than the other usually points to the same root cause, just further along.