REGULATION
Pianos should be regulated about every 10 years depending on the make, model, and the amount of use. If your piano is not responding to your touch like it used to, it may need regulating. When properly regulated, each note will respond the same as the next note. Evenness of touch is very crucial for the piano student trying to develop good technique.
The process of regulation involves very precise adjustments of all the moving parts of a pianos action and other parts that relate to playing the piano. Sometimes only minor adjustments are needed which is relatively inexpensive ($200 - $400). After many years the felt becomes hard and worn, sometimes even damaged by moths, misuse, or neglect. When re-felting is involved, this can become an expensive job. The best way to avoid problems is to have your piano serviced regularly by a qualified, experienced technician.
Regulation puts all the parts back to the original factory specifications. Key height, key depth, hammer travel, hammer let off, spring adjustments, damper adjustments, and alignment of many parts all come together to make each note feel the same and help respond to the most subtle touch of the fingers. Touch sensitivity is very important to the pianist and to those learning to play piano.