I was looking at a few BMW and Mercedes forums and some people say that short drain intervals will cause more wear because the antiwear additives need time to cling to the surfaces and are washed off with "too frequent" oil changes. I'm not advocating unnecessarily short OCIs but if there's proof that clean oil will cause more wear, i want to know about it, that is new to me. Would it be because different additives are temporarily working against each other if you switch brand/viscosity? I know a few people changing their oil every 5k km (3k miles) and and while i tell them to run it longer, they all have the healthiest never opened high mileage engines i know, some well over 500k km. Educate me because i am not gullible enough to believe that without proof.