Most extension-spring repairs on a single commercial bay are a same-visit job once the truck is on site with the right stock, since that hardware is common enough to carry. Track alignment and roller swaps go quickly too. Where it slows down is parts that don't match anything on the shelf - a nonstandard opening size, a panel profile no longer made, or a drive unit specific to a brand that stopped supporting older models. In those cases we order the part and come back, and we'll tell you that up front rather than promise a same-day fix we can't back up. A full door replacement, when the frame or track is too far gone to patch, takes longer to schedule than a repair, mostly because panels are made to order, not pulled off a shelf.