Which benefit of an oil change is highlighted in the consultants' discussion?

The benefit highlighted in the discussion about oil changes focuses on longer engine life. Regular oil changes are crucial because they ensure that the engine's moving parts remain well-lubricated, which minimizes friction and wear. Fresh oil helps to carry away contaminants and sludge that build up over time, protecting the engine components. When the oil is clean and at the correct level, it contributes to a more efficient engine function, which can directly extend the longevity of the engine.

While preventive maintenance is a broader concept that includes oil changes and is important in vehicle care, the specific focus here is on how maintaining clean oil can lead to a longer engine life. Improved fuel efficiency and lower emissions are valuable benefits of regular oil changes as well; however, the primary aim of an oil change is to maintain and protect the engine, thereby ensuring its durability and functional lifespan.