The first sign is usually noise: a grind or a rhythmic squeak that gets louder as the door travels, not a one-time pop. On original steel-roller setups common in this part of Hamden, the sound often shows up worse on cold mornings - Connecticut sits in a severe cold climate band, and steel rollers that have run dry for decades seize harder once the grease in the bearing stiffens.
The second sign is motion, not sound: the door hesitates or jerks at the same spot on every cycle, which usually means a roller has flattened on one side and is catching the track seam. Left alone, that flattened roller starts wearing a groove into the track itself, which turns a $20 part into a $150 track replacement.
If the door comes off the track entirely on one side, stop using the opener and call - that's a roller or bracket failure already in progress, not a sound you can wait out.