Coils lose tension capacity
Lubricant on tracks and hinges dries out faster in sustained high heat, galvanized spring coils lose a little tension capacity with repeated thermal cycling, and steel panels expand and contract enough over a summer to loosen screws at the hinge points. On a door built around 1987, that heat stress is landing on hardware that's already 35-plus years into its service life, so the margin for a worn part to fail is thinner than on a door from a 2010s build.
