15,000 mile oil change

[fabsroman]

I went to Wal-Mart yesterday to buy some Mobil 1 to change my dad's oil. Noticed that there was the regular Mobil 1 and then the extended life Mobil 1 that was guaranteed to protect for 15,000 miles. The extended life Mobil 1 cost 65 cents more per quart and I almost broke down and bought it, until I really started thinking about it.

Why do I want to keep the same oil in my car for 15,000 miles? Any particles too small to be caught by the filter will remain in that oil for 15,000 miles. Not only that, but by the time I get to 15,000 miles, there will be 3 times as many of those small particles suspended in the oil by the time I go to change it. Heck, the oil is pretty black with me changing it every 5,000 miles as it is.

Do any of you guys use this stuff, and if so, do you really keep it in your car for 15,000 miles? Is it worth the extra 65 cents per quart?