The inner playing mechanism, called the “action” of a piano, is an amazingly complex and sensitive machine. Like any other machine, it needs to be kept in adjustment so that it works the way it was meant to work when it was built. Each Key on your piano has over 25 points of adjustment that need to work together to produce the sound you hear when you play just one note!
In order to compensate for wear, compacting of cloth & felt, and changes in wooden parts due to humidity, periodic adjustments must be made. Keeping the correct relationship between every part will prevent unnecessary wear, and will make the action “feel right” – that is, each key will function smoothly and evenly throughout the whole keyboard. No more sticking keys, uneven feel, notes that don’t do what you want them to do, pedals that don’t work properly, squeaks, clicks, rattles, buzzes and so on.