Publisher Summary The preventive maintenance schedule can be defined as fixed-interval maintenance that is done every month, every quarter, every season, or at some other predetermined intervals. That timing may be based on days, or on intervals such as miles, gallons, activations, or hours of use. The two main elements of fixed-interval preventive maintenance are procedure and discipline. Procedure means that the correct tasks are done and the right lubricants applied and consumables replaced at the best interval. Discipline requires that all the tasks are planned and controlled, so that everything is done when it should be done. Elements of procedure include the following: first, listing of all equipment and the intervals at which they must receive preventive maintenance. Second, a master schedule for the year that breaks down tasks by month, week, and possibly even to the day. Third, assignment of responsible persons to do the work. Fourth, inspection by the responsible supervisor to make sure that quality work is done on time. Fifth, updating of records to show when the work was done and when the next preventive task is due. Sixth, follow-up as necessary to correct any discrepancies. Further, a record system should be kept on every instrument. Test equipment and measurement standards should be labeled to indicate the date of last calibration, by whom it was calibrated, and when the next calibration is due.