On average, in a fairly stable environment a piano should be tuned at least every six months to a year. Any longer than a year and extra work may be required to bring it back into stable tuning. Pianos exposed to changing humidity, such as a home heated in the winter but humid in summer, or other environmental extremes such as an arid climate, will need tuned more often. Any piano that is moved to a new location will need to be tuned. It may be best to let the piano adjust to the new environmental conditions before tuning, if possible; otherwise the piano may need tuned again soon as it adjusts to new humidity levels. Professional pianists often require that their pianos be tuned before every performance.
This simple, free, online piano tuning tutorial tells you how to tune a piano yourself, including exactly what tools you need and where to get them.
The main reason is changes in humidity. Much of a piano's workings are wood, which shrinks and expands as humidity changes. For example, as the home heating season begins, and dry, heated air replaces more the humid air of other seasons, the wood dries and shrinks. This reduces tension on the soundboard, and the notes sound flat. Other common reasons a piano goes out of tune include the jostling of a move, or loose tuning pins that slip. If the same notes tend to go flat time after time, it may be that the tuning pins are slipping, reducing tension on the strings, thus making them flat.
This depends on the market and the skills of the tuner. There are different levels of skill among paid tuners. Some just tune and may perform limited repairs. "Piano technicians" may perform various degrees of repair and more involved procedures such as voicing. There are credential criteria for technicians, maintained by the Piano Technicians Guild. Generally, a basic, maintenance tuning starts at $100 to $150 and goes up depending on the work needed. Any repairs will add to the expense.
It is possible for the novice to tune his or her own piano, on a very basic level, such as touching up troublesome keys, or an emergency check before a recital. It requires a few special tools, some knowledge of the technique and patience. It also takes care not to damage the piano. For a tutorial on how to tune a piano, see this website, How to Tune Your Own Piano. Note that a full and proper tuning, as well as repairs, will be best handled by a professional.
A pitch raise is essentially an extensive tuning that must be done on a piano that is very out-of-tune, such as one left untuned for several years or more. When a piano is left untuned for a long time, so many strings become out of tune that the tension across the entire soundboard changes. In this condition, tuning one string will affect the tuning on other strings. A vicious cycle ensues where previously tuned notes lose tune every time a new note is tuned, like a dog chasing its tail. To correct for this, the tuner will do a pitch raise, where the every string's tension is adjusted in one pass, to bring the tension on the entire soundboard close to what is desired. Then, often after a resting period, the tuner can perform the precise tuning of individual strings without affecting the others. Several passes may be needed before the pitches stabilize.
In the simplest terms, a tuner primarily focused on tuning the strings. A technician tunes the strings as well as performs other more mechanical services like repairs, regulation and voicing. In practice, many people who call themselves "tuners" can perform at least minor repairs. In professional terms, a piano technician has taken additional schooling and met certification requirements that prepare him or her to service all parts of the piano, not just the strings and minor repairs.
The piano has many working parts beside the strings, which need maintenance and repair. Beyond repairs, the other two primary tasks that are needed to get the best sound out of the piano are regulation and voicing.
Regulating the piano is essentially servicing the way hammers hit the strings. The mechanical connection including the key, the hammer and the structures in between are called the action. Adjusting these is called regulating the action. The technician can adjust how the keys feel when you move them with your fingers as well as how hard the hammer strikes for a given force on the key. Essentially you are adjusting how the piano "feels" as you play it. As a piano ages, the springs and tensioners may break or slip, and need replacement. Or the player may want a different sound from the piano, perhaps louder or brighter, and regulating the action can be part of this change, though specifically attending to the tone of the piano is calledvoicing.
Voicing is adjusting the overall tone of the piano, on a scale from mellow to bright. Much of it has to do with the felt pads which cover the hammers. These may wear down or harden as the piano ages, altering the tone, and need replaced or serviced. Or, perhaps the player prefers a more mellow or brighter tone than the piano presently has. The piano can be customized to this preference by replacing the felts with those of a different consistency.
Becoming a good piano tuner requires a good ear and lots of practice. Unfortunately, classes in beginning tuning at the local community college are just not common. Apprenticing under an experienced tuner is the best approach. Becoming a piano technician, that is, regulating the action, voicing or performing repairs, requires knowledge, which can be gained in study with materials from a professional organization, such as the Piano Technicians Guild. Such organizations offer testing to award certification credentials.