Usually a repair
If the panels are sound, the fault is almost always a part that can be repaired.
- The door will not open, or opens a few inches. That is a spring.
- It is loud, jerky or shakes. That is rollers, hinges or lubrication.
- It reverses or will not close. That is sensors or settings.
- One dented panel on a door that is still made. A single section can often be swapped.
- The opener has died but the door moves freely by hand.
Usually a replacement
Replace the door when the panels themselves are damaged or can no longer be matched.
- Wood panels that are soft, split or rotting at the bottom.
- Steel panels creased across the middle, which weakens the whole section.
- A door old enough that matching sections cannot be found.
- Several sections damaged at once, such as after backing into it.
- You want an insulated door and the current one is a single skin of steel.
The honest test
Disconnect the opener with the red cord and lift the door by hand. If it rises smoothly, stays where you leave it and the panels are straight, the door is fine and whatever is wrong with it can be repaired.
Be wary of being quoted a whole new door for a problem that started as one broken part.