Why keep a piano tuned?
Upright, grand, and console pianos are strung at a tension of about 40,000 pounds, thats 20 tons! That's why it is very important to keep a piano tuned. If the tension is allowed to drop the whole piano is affected. Pianos are tuned to the standard A-440 pitch unless otherwise requested or if the piano will not hold that pitch (which may be the case with some very old pianos).