I've been reading Mobil 1's website and they mention nothing positive about extended drain intervals. Actually, they mention that it is possible, but they don't recommend it as they say to follow your manufacturer's drain intervals.
That's because there ISN"T anything positive about extended drail intervals. Think about it: What does oil do in an engine? Lubricates, cools and cleans. First, lets look at the "cleans" part of oils job. Oil helps clean your engine by holding contaminants in a suspension (itself) and passing them through filter media to remove as much as possible. This is an ongoing and continuous process, although the filter doesn't get everything. Here's where we hit the first bump in extended drain intervals: Where does all the contaminants go? The filter? It can only hold so much before it becomes ineffective and either fails, allowing all sorts of stuff back into the engine, or begins hampering the engine's ability to circulate oil. So then you'd need to change your filter with an engine full of dirty oil on a regular basis, which is messier and more difficult than just changing your oil like you should. So do these oils that tout longer drain intervals have some magic susbstance to convert those contaminants to something harmless? Something that won't block filter media and change their inherit abrasive properties? Nope. They won't, the manufacturers just use the fact that the synthetic oil itself has properties of longevity to sell you on the false promise you'll save money using their product over a competitors. Mobil-1 doesn't do that. They don't need to.

Now, back to our contaminant-laden, yet still slippery engine oil. Since we've de-bunked the magical self-cleaning properties of "extended run" oils lets look at the next bump in this thought process and oil's other important job: Cooling. Our engine oil does a pretty good job in moving heat away from vital engine components in its lubrication cycle. But if we've now burdened it with the additional job of hauling around a mass of foreign matter because we're too frugal to change it, then its thermal properties as a whole degrade significantly. The wonderful synthetic BY ITS SELF has fantastic thermal properties, but now it's loaded up with contaminants. What are their thermal properties? Hmmm, lotta carbon in that suspension, definitely not a good thermal carrier. So, in addition to reducing its ability to clean the engine effectively we've now stripped away our oil's ability to cool as well.

Do the math, think in all the circles you care to and then stare at your wallet. More frequent oil changes (no matter what brand) or more frequest maintenance? You can read all the marketing hype to convince yourself otherwise, but the writing is on the wall of every maintenance shop in the world: Frequent and consistent oil changes make for a well maintained engine.

The choices I make come from real-world research and performance. That's how I came to be such a Mobil-1 fan. I don't buy Exxon or Mobil gas, or any of their other products for that matter. But the professionals in the aviation, marine, racing and many other fields chose Mobil-1 for a reason. I didn't buy then, I found out why they were using it and THEN I switched. From the Oil Sands of Alberta to the Goonyella Mine in Australia, Mobil-1 is a preferred industrial lubricant. Folk in the big $$$ industries can't afford to use what's flashy or has the best advertising gimmick, their day and dollar depend on production and reliability. Oh, and regular oil changes at specified intervals based on conditions.

I'll stick with and keep recommending Mobil-1.