The Symptom
The door usually tells you before it fails outright. It starts with a shudder or a hitch partway up the track - the opener straining against a spring that's lost tension. Then you'll hear it: a grinding or squeal from the rollers, worse in the heat of the day when the metal's expanded and the old grease has thinned out to nothing.
Some doors reverse on their own halfway down, which usually means the opener's force setting is fighting a spring that can't hold its half of the door's weight anymore. Others just get heavy - you notice it lifting the door manually during a power outage and it barely moves. A cracked nylon roller sounds different again: a rhythmic thump-thump as the flat spot on the wheel hits the track once per rotation.
What all of these have in common is that they show up gradually, then fail all at once, usually the week you need the door most. If your door is doing any of the above, treat it as the hardware telling you it's near the end of a normal service life, not as a one-off glitch.
Can You Do This Yourself
Some of this is fair homeowner work. Lubricating rollers and hinges with a light garage-door-specific grease, wiping down and inspecting the track for dents, and tightening the lag bolts on the wall brackets are all things you can do safely with the door in the down position and the opener unplugged.
What you should not do is touch the torsion spring itself. A wound torsion spring holds enough stored force to break bones or worse if it lets go while you're working on it, and the tools to do it safely aren't something most garages have lying around. Adjusting opener force settings past a certain point runs into the same problem - if the spring is already weak, cranking the opener to compensate just masks the real issue until it fails harder.
Our honest limit here: if your door is original to a 1980s or 90s build and one spring has gone, we're going to recommend replacing both springs on the shaft, not just the broken one. The second one is on the same clock and it's cheaper to do the job once.
