Median household income in Mount Pleasant runs around $49,897, noticeably under the broader service area's median of $70,163. That gap is part of why the approach here leans toward repair before replacement whenever the door and track are sound enough to justify it. A torsion spring job or a roller and cable replacement on a door that's otherwise in decent shape costs a fraction of a full door swap, and for houses built in 1981 the frame and track are often still good even when the springs are shot.
We won't quote a number here, because the honest cost depends on what's actually broken, and that's not something to guess at from a build year alone. What we will say is that the age of the housing stock in Mount Pleasant tends to push jobs toward spring and opener repair rather than full replacement, simply because the hardware era holds up better than the moving parts that cycle thousands of times a year.
Where replacement does make sense - a door that's rusted through, delaminated panels, or a track bent past straightening - we'll say so instead of patching something that won't last another winter.