A single frayed or snapped cable, caught before it does more damage, is usually fixed in one visit - the spring gets locked off, the old cable comes off the drum, new cable goes on, and the door gets re-tensioned and run through a few cycles before the tech leaves. Where it runs longer is when the cable took the bottom bracket or a section of track with it on the way down, which we see more often on the original, unreplaced hardware that's common on the 1984-vintage doors out this way. That's a repair, not a quick swap, and it can mean a second trip if a bracket or track section has to come from stock. Either way, the door doesn't sit open and unsecured between the call and the fix - we leave it closed and safe before anyone heads back to Everett.