In a piano, the component which suffers the most physical deterioration is the Action. The Action is a complex array of hundreds of moving parts, made of felt, wood and metal. After a time, these felts wear through or become hard, causing rattling sounds. The wood may become brittle and break and metal can rust or corrode leading to poor mechanical movement. An action overhaul will involve replacing any worn parts, or any parts suspected of causing problems in the near future, ensuring your piano will play well for years to come.