Most calls from Union City start the same way: the door stops halfway with a bang, or it opens fine in the morning and won't budge that evening. The bang is almost always a spring letting go under load. The evening failure is usually a motor that's been straining against a spring that's already lost tension, and it finally trips its own overload protection.
On the 1979-era chain-drive setups common here, you'll also hear it before you see it - a grinding or clicking from the header as the chain skips over a worn sprocket. That's a cheaper fix than a dead spring, but if you ignore it, the chain can jump the track entirely and jam the door open or shut.
Less common but not rare: a cable that frays where it wraps the drum, which shows up as the door running crooked, one corner dropping faster than the other. Left alone, that turns into a torn panel or a door that comes off the track completely. Any of these is worth a call before you try to force the door through another cycle.