of the various exemplary embodiments of the present invention shows the time remaining until the next scheduled evaluation and or preventative maintenance i e the lcd shows the measured time interval to the next scheduled evaluation and or preventative maintenance as a reverse countdown in the various exemplary embodiments wherein the lcd shows the measured time interval as a reverse countdown the initial time value shown by the lcd is preferably the value of the predetermined time interval for example if the predetermined time interval is 360 days at the time the timing device is initiated the lcd preferably shows a time value of 360 preferably as time passes the amount of time until the next scheduled evaluation and or preventative maintenance will become smaller and approach a value of zero 0 in the various exemplary embodiments of the present invention when the predetermined time interval is reached that is for example when the lcd of the timing device as a reverse countdown shows a value of zero the lcd preferably continues showing the amount of time since the predetermined time interval was reached as a negative number for example if a predetermined time interval was reached a week prior the lcd shows for example a negative seven u2212 7.