Piano tuning is the act of making minute adjustments to the tensions of the strings of an acoustic piano to properly align the intervals between their tones so that the instrument is in tune.
Pianos go out of tune whether they are played or not due to changes in humidity and temperature. Your piano is designed to sound its best when tuned to A440, which is the international pitch standard. Piano manufacturers and technicians recommend that a piano be tuned at least twice a year.
Restoring a piano means that a major component of the piano is replaced such as the strings, pinblock, bridges, soundboard or action parts. Restoring a piano returns it to its original condition or even better condition. It can also extend the life of the instrument. In many cases, a complete restoration can cost less than the price of a new piano.