For a door of the age typical here - 1990s build, steel track, standard roller size - we carry the track sections, roller brackets, and nylon rollers that fit that hardware on the truck for most calls. Where we sometimes come up short on the first visit is a door that's been upgraded with a non-standard track width or a heavier insulated panel added later; that hardware isn't something we stock in the truck by default, and if that's what we find, we're back out once the part's in hand rather than finishing same-day. We'd rather tell you that before we start than quote a fix we can't actually close out. Cable and spring work tied to an off-track repair - if the cable frayed when the door jumped - gets handled the same visit in most cases, since that's common wear we expect on doors from this build era and keep on hand accordingly.