A full roller set replacement on a single door, done from the truck stock above, usually runs under two hours once the technician is on-site - the drive from Terrell is the longer part of the trip. If hinges need replacing too, or a cable's binding from the worn roller dragging on the track, that adds time but rarely a second visit.
What changes the timeline is the track itself. On a 1977 door, if the track has rusted or bent from years of a misaligned roller grinding against it, straightening or replacing a track section takes longer than the roller swap alone. That's the one thing we can't quote exact time on until we see it.