A sofa is the only thing in the house that takes hours of direct skin contact every day and never goes anywhere near a wash. Body oil transfers off forearms, hands and the backs of heads straight into the weave, and it keeps going in at the same three or four spots night after night. That is why the armrests go dark and shiny long before the sides of the piece look worn at all. It is not neglect and it happens to every sofa that gets used. It also lifts, provided somebody uses the right chemistry with enough dwell time rather than scrubbing at it.
The care code decides everything else, and reading it is most of the expertise in this trade. It is on a small tag beneath a seat cushion or stapled inside the frame. W means water-based cleaning is safe. S means solvent only, and water will leave rings uglier than the soiling ever was. WS accepts either. X means vacuum only, and any liquid at all will shrink or mark it permanently. We find that tag before we quote, and where it has been cut off — which happens constantly on reupholstered and inherited pieces — an experienced technician tests a hidden section instead of assuming. Book the inspection and that answer costs you nothing.
Then there is the half of the job nobody sees, which is the half that changes how a room smells. The crevices down the sides hold more debris than the entire visible surface. The back panel pressed against an external wall is usually the mustiest part of the whole piece, because it picks up condensation all winter. The underside of every cushion has taken years of sweat straight through the top. All of that gets done, along with the piping and every seam, and then air movers pull the moisture back out of the foam rather than just skinning the surface dry. Lock in a date and the full kit arrives on the first visit.