A quote over the phone is a range. A quote after we've looked at your door is a number. The difference comes down to what we can't see from a description: spring wind direction and wire gauge, whether the track is bent or just dirty, whether the opener's logic board is dying or the issue is a worn sensor, and what the previous installer did if the door's been serviced before.
Winters here are cold enough that steel contracts, lubricant stiffens, and torsion springs under load take more stress on the coldest mornings - this is a cold-climate service area, and that affects which springs and weatherseal we recommend, not just whether we can fix what's broken today.
What we can't price sight unseen: anything where the door has been hit, where the opening itself may be out of square, or where a homeowner wants to match an obsolete panel. On that last one, we'll be honest if replacement makes more sense than chasing discontinued parts - sometimes it does.