Counter mechanisms for measuring the useful life of a reposable or disposable device include an actuator that drives a counter each time the device is used, sterilized and/or two or more parts of the device are fitted together. A display may be provided to display the number of times the counter is driven. A signaling device may also be provided that is responsive to the device having been used a specified number of times (based on the actual number of uses, sterilizations and/or fitting of two or more parts together) to provide an indication of when the device should no longer be used. Further, a disabling mechanism may be provided to prevent further use of the device after the specified number of uses.