If your door and track date to the original 1960s or 70s install and the spring, rollers, and bottom panel are all failing around the same time, patching one part is usually money spent twice. We'll tell you straight when a repair is going to hold and when it's just delaying a full swap by a season.
Here's the honest limitation: we don't carry every obsolete part for every pre-1980 door on the shelf. Some of the narrower track hardware and older spring sizes have to be special-ordered, and that can push a repair out past what a same-week fix would cost in labor alone. In those cases, replacing the door with a current panel on new track is often both faster and cheaper over the life of the door than hunting down discontinued parts.
We're not going to push a new door on something that's got real life left in it. If a spring swap and a track adjustment get you another decade out of a door built in 1972, that's what we'll recommend.