On houses at this build era, the door usually gives you two or three visits before it breaks: a wobble that used to smooth out, then doesn't, or an opener that pauses before it lifts. If your spring is going, the door feels heavier by hand at the halfway point, before it ever fails outright. Cables show wear as fraying near the drum, visible if you look with the door up. A track pulling away from the wall on one side, more common on the wider double-door openings typical of houses from this period, usually means the rollers wore unevenly for a while before anyone noticed. None of these are emergencies yet - they're the signs that tell you which repair to book before it becomes one.