Well it's going to depend quite a bit on your driving habits and your maintenance schedule.
First, Maintainence:
To get good mileage it is imperative that you check your tires regularly and keep the air pressure at 33--37 pounds.
I had a friend, very artistic guy who just couldn't seem to "get it" when it came to cars, etc.
His OEM BF Goodrich tires wore out on his car in just 15000 miles. He said he couldn't understand it.
I asked him what pressure he ran the tires at? "32" was the answer.
Further questioning indicated that he thought they were at 32 when he bought the car "because the dealer would have set them correctly, right?"
and he checked tham at the one year point and finding them down about 10 PSI per tire filled them to 32 again.
Then rotate as you mentioned.
Some say every 5K, I do every 7k.
But I am also anal about alignment and balancing.
Alignment and balancing is critical to enjoying a car as far as I am concerned.
And if a car is misaligned you can go thru a tire or two in a couple of thousand miles.
Then there is HOW you drive.
You will shorten the life if you think the MO makes a pretty darn good sports car.
Leaviung rubber (even if it is only a little squeak), drifting thru corners and slamming the brakes will take their toll.
Then comes WHERE you drive.
You will get MANY thousands of miles moer f you set your car at 70 miles pre hour and just drive until they wear out. That's what they do at the test track in Texas and they routinely get 100,000 miles on a set of tires.
City driving is much more punisihing to the tires.
And then I guess the final variable is WHEN is a tire "worn out"?
Some take them to the wear indicators, but I drive in the rain a lot and do not.
We have had one member who drives fast, but sensible, almost exclusively on the highway, and does his maintenance, and he got almost 90,000 miles on his OEM tires! (Check out IVnurse posts)
As i look at my 20K tires (Due for rotation in a few weeks) I would guess that I will start looking real close at 30K and maybe buy new tires shortly thereafter.
I don't like hydroplaning.
And people that use these so called all weather tires say that when they get about 30K on they are pretty bad in the snow also.
So I see them as 30-35K tires. Others see it differently.
BTW, I personally will likely replace the Goodyear LS', with the same tire again.
I know a lot of people say that it is not a good tire, but these same folks have bragged about how well their MO handles and how quiet it is.
I think that it is a Good summer Tire.
Homer