I use synthetic in all my vehicles and change the oil every 5000 miles. I don't pay that much attention to time.
What I suggest that you do, if you are interested in determining how good your oil change regimen has, or has not, been for your engine, is to send the oil off to a lab to have it analyzed. Blackstone labs will do a standard oil analysis for $28.00. Go to their website and request sample kits. They are free. I have done several oil analyses on my 2002 BMW 530i and have been happy with the results and the information provided.
If you are interested in extended drain intervals (I am not) then you can pay addidional $$$ for a TBN analysis. Based on the TBN analysis the lab can make a recommendation on whether or not you can safely increase your drain interval. Many people that use the Mobil1 0w-40 that I use typically go 7500 miles between oil changes. I have stuck with 5000 even though my oil analyses have indicated I can go longer. Also, the attached indicates Pennzoil but I typically use Mobil1 0w-40 Euro formula. I took part in a Pennzoil market study and used their 5w-40 for a couple of oil changes. It was also good oil. Any oil that is BMW LL-01 compliant is good oil. Mobil1 0w-40 Euro was recently reformulated and lost their BMW LL-01 certification but I can't find a consistent supply of the Pennzoil LL-01 compliant oil so for now I'm still using the Mobil1.
Give the Blackstone oil analysis a try. It's good to have that information. I just changed the oil in my recently acquired 2011 Armada. The dealer had overfilled by about 1.5 quarts and used conventional oil and a cheap filter. I used the Mobil1 0w-40 and a Nissan filter and plan to send off a sample after about 5000 miles. I will post my results when I get them, in about 4500 more miles.
Now this is the kind of thing I am looking for.
The 2011 Armada recommends 5W30 but you are using 0W40! Now that is a thick oil. I would love to get feedback from you on how the oil performs in the long run. How many miles do you ave on your Armada?
We all know that all of us who frequent the forums do take care of our vehicles. I do take good care of mine. And would not put anything to hurt it, but will try to put anything in it that I think could help it and extend its life.
Talking about oils, I think of all the oils we put in our cars, I am using a grade different from what the manufacturer recommends. And my QX drives great!
Power steering fluid, I use another kind of fluid. Front and rear differentials, I use another kind of fluid. Center differential, I use oem, but plan to go with a different brand. Transmission, I go oem.
Brake fluid, I use dot 4, instead of dot 3 that is recommended. As big and heavy as this car is, I need my brakes to always be in top form (along with brake pads and rotors) and very responsive when I need them. With the dot 4 brake fluid, my QX stops on demand!
Now to oil change. If anybody here has time, just goggle 2016 Infiniti QX80 Owners manual. It recommends 0W20 to be used as first choice. Then the next line says it also recommends 5W30 and that 5W30 meets manufacturer's warranty. Basically that switching from 0W20 to 5W30 on the brand new 2016 is covered under manufacturer's warranty. So, this makes me believe that Nissan did not change anything in this engine and hence, I can switch to 0W20 if I wish with no problem.
Link below... Go to page 561 which is also page under chapter 9 section 9-2. top right corner of this page.
It is a widespread thing that car manufacturers are all going to 0W20 because of fuel mileage requirements. They claim it helps gives you better gas mileage. But the oil is very thin and so does not protect your engine as well as a 5W30 would protect it in the long run. The only reason now that I am feeling reluctant to use the 0W20 is just that my car is old and so engine protection and longevity makes 5W30 (or now that I think of it, maybe 10W30) a better choice for my QX with high mileage.