A New Opener
There are three reasons to replace an opener rather than repair it, and only one of them is that it has stopped working.
Short answer
Replace where the logic board has failed on an older unit, where the unit has no rolling code security, or where it has no photo-eye sensors at all — which on a pre-1993 unit is possible and is a safety matter. Repair where the fault is a specific replaceable part on an otherwise sound unit.
When replacement is the answer
A failed logic board on an older unit, where the board cost approaches the cost of a new opener.
No rolling code security, which means the code can be captured and replayed. This is a reason on its own, working unit or not.
No photo-eye sensors, which on a very old unit is possible and is a genuine safety gap — entrapment protection has been required on units sold since the early 1990s.
A worn-out unit where several things are failing together.
Where the door is being replaced anyway, because the labour overlaps and the new door deserves correct force settings from a current unit.
And where you want a feature the old unit cannot have: battery backup, a quiet belt drive, a wall-mount arrangement.
Rolling code
A fixed-code opener transmits the same code every time, which can be captured and replayed by somebody with inexpensive equipment. A rolling code unit changes the code with every use. If the opener is old enough that the remote has small switches on the back to set a code, it is a fixed-code unit and that is a reason to replace it.
When repair makes sense
A sensor, a wall button, a remote or a receiver fault.
A stripped gear and sprocket on a chain drive, which is a common and economic repair.
A capacitor, which is a cheap part and a common failure.
A chain or belt that has stretched or come off the sprocket.
A limit switch or a force adjustment, which is a setting rather than a part.
And a trolley or carriage fault, which is a part rather than a unit.
What to do at the same time
Have the door balance checked, because an opener working against an unbalanced door will fail early whatever you fit. This is the most important item.
Have the springs assessed, because fitting a new opener to a door with springs at the end of their life is doing the job in the wrong order.
Replace worn rollers, which reduces the load on the new opener considerably.
Set the force and travel limits properly and have both safety reverse tests demonstrated.
Have the sensors mounted at the correct height and properly wired rather than draped along the track.
And clear the old remote codes, and set up a keypad outside so a remote does not have to live in a vehicle.
Common questions
When should I replace the opener?
A failed logic board, no rolling code security, or no photo-eye sensors.
How do I know if it has rolling code?
If the remote has small switches on the back to set a code, it is a fixed-code unit.
What should be done at the same time?
The door balance checked and the springs assessed. An opener fighting an unbalanced door fails early.