Purchasing preventive maintenance (PM) servicing is a conscious and informed decision based on reflection and speculation - in a sense, kind of like buying insurance protection.
Purchasing insurance is risk management: you spend your dollars with the anticipation that you WILL need coverage and the insurance company collects your dollars in the risk that you will NOT need coverage. With PM service, you are limiting the risk that it will take more dollars to repair your vehicle when (not "if") it needs repair. You are paying dollars in advance in the anticipation that you would have to spend more money on repairs later if you don't keep your vehicle in top-notch condition.
Unlike the insurance company though, the automotive repair facility is NOT offering PM servicing in the hopes that you will NOT need repairs. We all know that equipment needs to be maintained to give long and reliable service. But more importantly, what the repair facility knows for sure is that great customer service builds a specialized group of loyal repeat customers - and loyal, satisfied customers recommend their personal repair shop to their friends! Why? Because their vehicles are well maintained and break down less frequently, for fewer dollars.