A standard torsion spring replacement on a residential double door, once we're on site with the right spring stock, runs under an hour - winding bars, safety cables, drum realignment, a full-cycle test. Single spring on a one-car door is faster. Where it stretches is diagnosis: if the door's been forced open with a broken spring for a few days, we're also checking cables, rollers and the bottom bracket for damage that happened while the door was running unbalanced, and that adds time to the visit, not to the spring wind itself.
Given the 1986 median build year here, we budget extra minutes on most Lake Alfred calls just for hardware inspection - older track brackets and worn end bearings show up often enough on doors this age that skipping the check is how a spring job turns into a return visit for a track problem we should have caught the first time.