2012 MX-13 NOX SENSORS

[BLOODSWEATTEARSMX13]

I own a 2013 587 Peterbilt with a 2012 455hp MX-13. This is one of the last first generation series MX-13 motors to come off the assembly line. I was needing to know if the NOX sensors on this motor should be replaced annually. I have driven the truck 161,000 miles since I purchased it 19 months ago and I have never replaced the NOX sensors. I was also curious if the NOX sensors life span and ability to function well can be maintained by taking them out and cleaning them periodically. Any one owing or working on this motor that can offer me some advice would be appreciated.