Over time, piano keys become out of level with each other, unevenly spaced, and tilted from side to side (out of square). This can cause the pianist some problems when trying to achieve uniformity of sound because the uniformity of touch is not present. It also looks bad from an aesthetic perspective.
Piano hammers are a critical factor in the tone of your piano. If your piano sounds harsh or too soft, it can often be remedied by giving some attention to the hammers.
Just as an author must master their language, a piano technician must master the theory of piano tuning. The technician must know what makes a proper tuning and how it is achieved, by ear and by machine. Once the technician has done so, they can achieve equally beautiful and correct tunings by both methods.
You may find that one or more of your bass strings makes a buzzing sound, as if something was making contact with the string that should not be. Often it will produce a sound similar to what you would hear if you rested a paper on the string, then struck the key. It can become quite an annoyance.
Old keytops can be removed and replaced with new, durable keytops that are sure to improve the appearance of your piano.