What does it mean to tune a piano, and why is it necessary?
A pianos sound is produced by felt hammers hitting strings (around 240 per piano). The length, mass and tension of a string defines its note.
Piano tuning is the tension adjustment of each string so they can produce the desired note and sound in tune.
However, sounding in tune is not the only purpose of tuning a piano.
Pianos are designed to sit at a certain pitch (A440). When tuned and maintained to this pitch the structures of the piano remain in a state of equilibrium, allowing the piano to stay in tune for long periods of time and prolonging the life of the piano.
When not tuned and maintained regularly, the tension and overall pitch of the piano will fall. This will make the piano sound bad and will reshape the wood of the piano affecting its overall strength and ability to hold a stable tuning. Raising a piano back up to pitch, though doable, is not only more expensive but the tension load added to the piano will further affect it's overall strength, stability and longevity.
Therefore, it is very important to have your piano tuned and maintained regularly.
Tuning a piano is akin to having a roadworthy for your car.