I cannot agree with anyone or any article that says oil color doesn’t mean anything. It always does mean something. It just doesn’t always mean what you might think it means.
When oil changes color, something has changed within the oil. Only an oil analysis can tell you for sure what has changed, but I agree with those who say it is not worth the cost to the average motorist. If in doubt, change it.
“Looks dirty” is really subjective. Medium brown can be someone’s “very dirty” where another may not consider the oil dirty until it is thick, black and gritty. If you have ever put clean oil in a tin can and held it over a fire, you will see it gradually darken to a deep brown. If you leave it there long enough, you will end up with a black gritty substance.
Heat alone will cause oil to break down, but in a vehicles engine, the oil is not only subjected to a lot of heat, it also gets subjected to a lot of shearing action due to friction. Most modern engines are sealed against external contaminants such as dirt, but some could get in eventually.
Older engines also start getting a bit of “blowby” when the rings start to lose their seal with the cylinder walls and that increases the rate of oil breakdown.
So I go back to my original criteria for an oil change, if in doubt, change it. It will help you sleep better even IF the engine could have gone a few more miles on the existing oil.