Interesting, before the advent of 6 yearly oil changes (unless the manufacturers recommended oil changes hours had been reached) based on oil analysis, BT used to change the oil annually but not the filter, again unless the manufacturers recommended oil changes hours had been reached, because most engines took years to reach the number of hours that the manufacturer recommended oil and filter changes.
However one big difference between a BT standby generator diesel engine and a boat diesel engine was that the BT engines used thermostatic crankcase heaters to maintain the coolant and lube oil at temperatures close to the normal operating temperatures, to allow the generator to pick up.to 100% rated load within 30 seconds of receiving a start signal.