The Piano Surgeon is expert at Piano Restoration and Repair.
Pianos have a limited lifetime, usually measured in decades. However, different parts have different lifetimes: for example, on a heavily used but well-cared-for instrument (e.g. in a concert hall), the hammers might last less than five years while the soundboard might last fifty years and more. Regular replacement of worn parts can, therefore, extend a piano's lifetime by decades – even indefinitely, provided that the piano's structural support (i.e. the frame) remains sound (and sometimes the frame can also be repaired).
In very used pianos, the frame and some parts of the action may remain in good condition, and piano rebuilders are able to restore or rebuild an instrument by replacing many components. These include the strings, pinblock, bridges, soundboard and ribs, hammers, and action. "Restoration" implies more replacement work than mere "repair" or "maintenance," and "rebuilding" implies yet more intensive work than restoration. However, there is no precise definition of these terms.
Credit: Piano maintenance