I print a lot so I go through a several sensors a year. I am a retired Mechanical Engineer, after looking at the worn out sensors I realized the issue was not the sensors wearing out but the filament was wearing a groove in the edge of the sensor until the filament no longer maintained contact with the internal sensor arm. So, I designed this cover that not only protects the sensor but the lead-in and out on the sensor cover eliminates the wear on the sensor prolonging its life. I have not had to replace a sensor in over a year.