[JimD]

With respect to oil change intervals I think a couple things. First, it is very hard to judge motives, even of an individual, more so for a company. There are probably a variety of reasons BMW greatly extended the service interval on oil & filter for the engine and eliminated changing other fluids.

I am from the school of thought that suggests more frequent changes help the vehicle last longer. I am aware not everybody believes this is true and some don't care because they think the difference will be seen by the next owner, not them. I'm not saying you are wrong if you are in one of these camps, just that I don't plan to let any of my vehicles see anything approaching 15,000 miles without an oil change. My Japanese SUV gets changed with synthetic every 5,000 miles. My bimmer get's it's oil changed annually which is about 7,000 miles. Once the free changes are up, I will probably switch it to every 5,000 miles too. That is probably more than necessary but the differential in cost is low and I'd rather err on that side. I did two oil changes early and I bought oil change kits from Tischer and United. They are much less costly than a trip to the dealer and are very convenient (stuff is delivered to your house for about $60).

I also changed the differential and manual transmission fluid early (less than 2K miles) and plan to keep doing it. The differential is a pain to suction out but it takes only about a pint to fill it so I will waste an hour every few years to get as much as possible out and refill with new. I like Red Line products for this and use the thicker MTL, not the ATF, in the manual transmission. That makes it shift a little stiffer when cold but I'm used to differential thickness fluid in a manual and cannot see how ATF is the right choice.

I recycle engine oil and generally just dump manual transmission and differential fluid in the same container for recycle. I don't think my more frequent changing hurts the environment. I'm not a tree hugger but as long as it is reasonably convenient for me to help out, I will.

Jim