Nothing lasts forever. Even the best built of buildings or tools eventually wear out. So you wonder, "Do pianos ever wear out?"
A good piano is a very tough piece of equipment. It can stand up to an enormous amount of use (and abuse) for many years. A few things it can't stand: children pounding the keys with hard objects, water spilled into it, extremes of heat and cold, moisture and dryness; these are a piano's arch enemies.
Under normal use, a good piano will last a couple of lifetimes. But eventually, wear will show up. The hammers will become flattened from hitting the strings and must be reshaped or replaced. Felt parts under the keys wear thin and must be renewed. Tiny felt bushings which form the "hinges" for moving parts, become loose and allow the hammers to flop sideways. These also must be replaced, a very time-consuming job. The strings themselves become crystallized and lose their rich sound. Other felt and leather parts in the action may wear out and have to be repaired or replaced.
The first thing to determine is, "Will this piano be worth the cost of rebuilding?" It takes a lot of work and money to make much difference in sound. Often, you're better off to trade for a new piano.
But, if the piano is a high quality instrument and very valuable for musical or sentimental reasons, it may be worthwhile to undertake rebuilding. This may be partial, simply replacing the worst of the worn out parts (cost: several hundred dollars) or it may be total, stripping down the piano completely and rebuilding almost everything. (cost: several thousand
dollars.)
Piano rebuilding is an exacting job, requiring special equipment and extremely careful, knowledgeable workmanship. Not all piano tuners attempt it. Don't allow anyone to start on your piano unless he's
recommended by your favorite piano technician.
However, done right, the results can be very satisfying and almost all of the original beauty may be returned to your piano for many more years.