for to do so would ensure obsolescence in a rapidly changing world. Maintenance and repair activity is required in order to ensure that devices are kept functioning within the limits imposed by the test criteria and to return devices to the required level of functioning after breakage or other failure. Additionally, safety and performance testing is required in order to identify unsafe or incorrectly performing medical devices that could pose a risk to either patients or staff. Such testing is usually performed at acceptance and then on a routine basis.