The clock movement might be so badly worn or damaged that it is in the customer’s best interest to replace it entirely. While replacing a movement in a modern clock with one of the specs is a completely acceptable procedure, it should never be confused with the act of ruining an antique clock by substituting an improper movement or replacing with a battery operated one. In most cases, replacing the movement has the advantage that the cost of labour and the movement can be determined swiftly and precisely.