11.   Either would also have required the replacement of considerable factory equipment, which would have caused a costly delay before the first production of the new models.

12.   Other setbacks required the replacement of a shuttle rocket engine and wiring outside the fuselage linking the external tank and the solid rocket boosters.

13.   Rechargeable batteries eventually get old and require replacement when they can no longer take a charge.

14.   They have washers that wear quickly and often require replacement.

15.   Three more have required replacement since the crash.

16.   Citizen also said that Japanese watchmakers were shifting to next-generation quartz watches that do not require battery replacement.