the 02 Frontier's FSM MA page has 3750m/6mths as schedule 1 (Extreme Duty)
75000m/1yr as Schedule 2 (normal duty)
They guidance suggests:
Follow Periodic Maintenance Schedule 1 if your driving habits frequently
includes one or more of the following driving conditions:
Repeated short trips of less than 5 miles (8 km).
Repeated short trips of less than 10 miles (16 km) with outside temperatures
remaining below freezing.
Operating in hot weather in stop-and-go “rush hour” traffic.
Extensive idling and/or low speed driving for long distances, such as police,
taxi or door-to-door delivery use.
Driving in dusty conditions.
Driving on rough, muddy, or salt spread roads.
Towing a trailer, using a camper or a car-top carrier.
Follow Periodic Maintenance Schedule 2 if none of the driving conditions
shown in Schedule 1 apply to the driving habits