On a newer door like the ones common through Grain Valley, a spring failure tends to announce itself cleanly: a loud bang from the garage, then a door that won't lift at all, or one that lifts a few inches under power and stalls. That's the torsion spring letting go, and on hardware this age it's almost never tangled up with other wear.
What you're less likely to see here than on older stock elsewhere in the service area is a door that's been struggling for months before it fails - sagging, dragging, opener straining. Houses built around 2002 haven't had the decades of cycling that wear a spring down slowly; the failure is more often sudden on a door that was working fine the day before.
If you hear the bang, don't try to force the door up by hand or with the opener. The cables carrying the load once the spring is gone can whip if the door's forced, and that's a hand injury waiting to happen, not just a repair. Leave the door shut, call it in, and we'll bring a spring sized for the door once we know what's on your house.