Name the component and the symptom.
The door, opener and controls do different jobs. Ask which component is at fault and how it relates to the movement or sound you noticed. A replacement should have a reason beyond the age of one part.
Compare like with like.
Check which parts, labor and warranty terms each quote includes. Ask whether several recommended items are all needed for the fault or whether some are separate improvements. A price from a neighbor's different door doesn't settle your job.
Understand what repair would leave behind.
Wear, damage elsewhere, parts availability and overall condition may affect the options. Ask what would remain unchanged with a repair, and which problem a larger replacement would solve.
Keep the opening safe while deciding.
Stop using a crooked, stuck or visibly damaged door. Keep people clear and leave spring, cable and tension work to an appropriate technician. You can ask useful questions without operating or dismantling the mechanism yourself.