Why does my Piano go out of tune?
Piano strings are under terrific strain. This tension will cause the wire to stretch and the string to go flat. This stretching of the strings is especially bad during the first year or two after a piano is built but will, to some degree, continue for the life of the instrument.
The new piano has new strings which will stretch out of tune very quickly, and it should be tuned at least every six months for the first two years after its purchase. How long the piano dealer had the instrument in his store, and how often he had it tuned would be a factor. The owner of a new piano should be advised to have it serviced at this interval.
Weather and climate changes work against the piano. In the winter when you heat your home, the humidity drops. The wood frame shrinks. In the summer the humidity goes up, the wood frame expands. The result is that the wires and tuning pins slip. Believe it or not, a concert grand can shrink or grow a 1/2 inch in overall length during these extremes!
A Major cause of a piano going out of tune is a change of relative humidity.
Temperature changes are another big reason for pianos going out of tune. The metal plate and strings expand as the temperature rises and contract as the temperature falls. This continual expansion and contraction has a great effect on the tuning.
Because you pound on it! Playing a piano is not bad for it. But if you play hard... it will go out of tune faster.
The piano tuner, if he does not do his job correctly, can be responsible for the piano not holding a good tune. If he neglects the Test Blow or does not tune down, his tuning may not hold.
The piano owner, by not having his piano tuned at regular intervals, is often the contributor. A piano which has not been tuned for many years simply will not stay in tune with only one tuning. If the strings must be stretched up too far to bring back into tune, they will not hold and another tuning job in a short period of time will be necessary.
Because you move it around!
Age gets to a piano!