I agree with using synthetic even if you trade-in your vehicle every 3 years, I've done so and only changed my oil like 2-3 times in the 3 year leases I've had. Another benefit of synthetics is more horse power, cooler running engine in the heat and lower temp protection up to 60 below zero Fahrenheit, also better MPG. I use the recommended grade from Infiniti, the QX60 calls for 0W20, mostly to get better MPGs cause the thinner the oil the faster it circulates and protects, and the better the gas mileage. Mobil is good but if you can get Amsoil it may be better, it all comes down to what the oil base stock is, and all oils use different ones. Some are synthesized petroleum, with complex molecular structures that can degrade and breakdown causing build up of sludge in the engines (for example Mobil1,and generally all oil company manufacturers of their own synthetics) , others (like Amsoil) use proprietary synthetic blends of lab made chemicals that make the oil more stable and the compounds they are made from have a simpler molecular make up that makes their film strength stronger, and any sludge build up non-existent; the example I use is if you compare the molecular structure of a diamond its simple is pure carbon, and that's what makes it the strongest substance known to man. Likewise if you make a lubricant of simple bonded chemical molecules, that lubricant will be stronger to protect the metals engines are made of better. But, as long as you use some type of synthetic it will be better than conventional oil every time.