What a crock of horse manure. Severe service to this guy is anytime the key is turned. When a motor sits and idles, it's the easiest running time the motor will ever have. Minimal stress and strain on the motor parts. cruising on a highway is also easy running. That's why you get your best mileage on the highway. Hard service is when your vehicle is loaded to capacity and or towing a trailer, boat, or other heavy item . Let's talk about "Genuine factory parts". I don't know of any mfgr that MAKES its own oil, oil filters, power steering fluid, air filters,freon, anti freeze, light bulbs, brake pads,brake fluid rotors, transmission fluid and filters, or wiper blades. The mfgr just puts out a spec and accepts bids from makers of those products and the lowest bidder usually gets to supply them the the auto maker as factory fluid.The reason you pay more at the dealer is because they are the "middleman". As long as you have a spec to follow, you can use "aftermarket" products with similar or better results.Look at how many cars never see a dealership after they are bought, and last hundreds of thousands of miles. Thousands of auto parts stores wouldn't be in business if it didn't work that way.,,