A spring that's done 10,000-15,000 cycles doesn't always announce it's about to go. On the two-car doors common in this part of Algonquin, you'll often hear a loud bang in the garage, then the door won't lift past a few inches, or it slams down fast when someone tries to close it by hand. Cable fraying tends to show up around the same age as the spring, since both parts wear on the same cycle count. We also see one-spring systems on older single doors where the other side was never upgraded to match - that imbalance speeds up wear on rollers and the opener's drive gear. None of this is unique to one house, but it tracks closely with when the system went in, and a lot of this area's systems went in around the same stretch of years.