When and how often a DPF needs to be serviced depends on several variables. Engine RPM, duty cycle, idle time, fuel quality, engine oil quality and maintenance procedures can all have a tremendous influence on how frequently a DPF needs to be serviced. The most common methods for triggering a DPF service light are based upon the hours of operation, mileage or backpressure differential in the exhaust system. Always use the OEM service manual recommendations as guideline for your application. You may need more frequent cleanings based upon application and duty cycle.