Start with the manufacturer schedule
Every vehicle has a time and mileage interval, and the earlier of the two applies. That schedule assumes reasonably average use.
When to service more often
- Mostly short journeys where the engine never fully warms up
- Heavy town or stop-start driving
- Diesels that rarely get a sustained run
- Towing or carrying heavy loads
- Engines with wet timing belts or variable-vane turbos
What you actually save
Fresh oil protects turbos, timing components and DPFs — all of which cost several times more than a service. Shortening an interval is the cheapest insurance on a modern engine.