daily driver TJ with 41 miles to work and 41 miles back home. I change between 4-5 when its conveinent to do so with my schedule. My oil had been getting black but was because of a leaky injector, problem is solved and the oil stays much cleaner. I don't stress over it and use dino oil because its economical and does the job. If it bothers you to run longer, have blackstone labs run a sample. For $25 bucks its a good test that will tell you what your engine is doing to the oil. Or just change the filter one extra time at mid point interval, that would give you clean filtration. Had a friend in college that drove a 73 ford maverick and never changed the oil just topped it off. That thing kept going and going when all conventional logic said it would blow up. When he sold it he had 230,000 on the odo. He put all but 60,000 on it.