I like saving resources and sometimes take it to the extreme. That is why you do not hear many people talk about this type of odd issues.

Talking about transmission, it is a simple wear and tear concern. More the shifts more the wear. My last car went, with original automatic transmission, over 190k miles. I bought it at 125k and the previous owners did not take care of it. I started replacing the fluid every 7k miles and drove such that it does not shift much. Currently its 3rd to 4th shift is going. How many manufacturer will tell you to change transmission fluid every 20k miles let alone 7k miles?

On my 850, I notice a good difference, maybe unnoticeable to many, after replacing fluid at 20k miles. I plan to move the interval to 10k or 15k.

Manufacturers care for reputation but also sets the standards for durability. Why do things stars falling apart right after the warranty expires? How many car manuals say that it is a good idea to warm up the car after admitting, in the manual, that the engine runs best at its operating temperature (VW Passat 2002 owner’s manual)? I do not think this ‘best’ is only about efficiency but also about durability. And the list goes on....

Ronjon