I changed the oil in my Mustang once a year. It seen 1-1.5k per year.
My truck just went a full year before I changed the oil out. Took me a year to go from 5k-9k. I used Mobil 1 Extended 15kmi rated oil, PureOne filter. Didn't burn anything noticeable. I changed the oil at 4kmi rather than 5 or 6kmi because it was getting dirty from the K&N.
Neither vehicle was in a temp controlled environment.
I just make sure the truck warms up fully here and there and that's all to keep out condensation!
Most people I know run oil in their lawnmowers and snowblower for years without out ever adding or changing.
The oil goes bad from heat and dirt which breaks it apart, other than that, it does not go bad.
I think you should just keep en eye on it. Maybe it was a mixture of you only maybe not adding enough oil and burning some as well? The oil filter will hold nearly 1qt of oil..btw and some even more.

 

I disagree with this comment. Engine oil additives do not break down over time, they break down down with usage.

There can be issues with oil building up sludge from lots of cold starts, short trips where the oil does not get up to operating temps to burn off any moisture, etc...

A friend of mine from work has a newer Corvette that is not his primary vehicle. The computer looks at multiple factors when deciding how long before the oil change light comes on. He commented months ago that the 'Vette went more than a year before the oil light came on. As an engineer myself, I trust that Chevrolet and all the other car manufacturers that have this feature in newer vehicles have "done the math" and tested this before unleashing it on their vehicles. Particularly, if the vehicle in question costs upwards of $50K or more.

The 3 month rule is just bogus today. When oil was dirt cheap, why not? But with the cost of conventional oil, not to mention the price of a good synthetic, it can really save some money to do some homework and understand the factors that dictate when to change engine oil.

 

Not just increased expense, but the the 3K rule also increases the waste stream.

I've changed the oil in my vehicles at 5K for decades. When I got the Ram and handed down a Nissan PU to my daughter. Running like a top with 300K on it, and oil changes at 5K.

I was a little surprised to find that my wife's new Hyundai has a reccomended interval of 7.5K.

NNY

 

I wish the explanation was that simple, but I specifically remember, and even found my post here last year when I did it, that I put 6 qts. of oil in and changed the filter and then realized I needed another quart and went and got it and put that in too. And, I always run a vehicle at idle after an oil change and then shut it down, check for any leaks, and then check the dipstick - and I wouldn't have just let it go if it wasn't right. The oil had to have burned off or leaked out and I don't think it leaked. I haven't smelled any burning and haven't noticed any smoke but maybe it was a slow burn over that period of time and just wasn't noticeable. I've been looking for spots, smelling for oil, and looking for smoke since I first posted this thread and so far, I haven't noticed anything. And the dipstick still shows full.

I'm leaving tomorrow for a 600 mile trip to Indiana. I'll check it as I go, etc. and see what reveals itself, if anything.

 

I have an 04 2500hd with the hemi. I bought it in 08 with just over 26,000 miles and put amsoil and eao filter in it. after a year i changed it putting 5k on and it ate 2 quarts in that year. I changed it feb of this year putting 16k on it since 09, and only added 1 quart in those two years. I have done this for a co-worker and his 04 ate a few quarts for the first year and settled after that. Must be a synthetic thing, would expect it more with higher mileage vehicles, over 30k, just hang in ther and check it more often it should settle down to normal.