On a door this age, trouble usually announces itself before it fails outright. A grinding or popping sound when the door travels means a roller or bearing is worn, not lubricated. If the door feels heavier than it used to when you lift it manually, the torsion spring has lost tension - that's wear, not a broken part yet, and it's the clearest sign a spring is near the end of its life. Uneven closing, where one side of the door dips before the other, points to spring imbalance on a two-spring system, common on these 16-foot doors. In our cold-moderate climate here, winter mornings can also make stiff old grease more obvious - a door that moves fine in July and groans in January is telling you the lubricant needs replacing, not that something's broken.