Older pianos or instruments that "just don't feel right" can sometimes need more than a typical regulation can offer. Older parts wear out and need replacement, and even new pianos can sometimes have problems with the touch and weight of the action. Action analysis is a system through which a technician can measure certain aspects of the action and can often provide a solution that optimizes the performance and feeling of the instrument. Action rebuilding refers to the replacement of parts such as hammers and their associated shanks, wippens (the transmission source of power) and various other aspects to bring the action back to a state of proper performance. Often these two operations are performed in concert to revive older instruments or solve action problems for the pianist.