My goal is to treat each customers car like it were my own car. I suggest repairs that I would do if the car were mine. If it's a high mileage vehicle I would change the transmission fluid and filter, powers steering fluid and brake fluid as well as any fluid in the car. Dirty fluid will cause a component to fail early like the master or slave cylinders for the brakes, the rack for the power steering all expensive to repair. Cooling system failure can cost several thousands to repair what would have cost $120 to $160 to flush, change the hoses, radiator cap and thermostat. and blah, blah, blah

The timing belt can cause catastrophic damage to the engine, if it's changed at regular intervals along with the water pump it can save a breakdown and a loan to repair the car....