Simply put, I will be changing my fluid and filter at the same time I change the friction materials or other components in my transmission.
Regardless of whether you change the fluid every 100,000 60,000 or 3,000 miles the friction material on the plates will inevitably wear, as will the electronic solenoids/valves and the rubber components. The fluid does break down over time, but the nice expensive synthetic fluids used in modern transmissions like in BMWs lasts a really long time before losing its lubricating and hydrolic properties.
If the fluid was overheated by repeatedly towing heavy loads then it can lose it's viscosity and should be changed, or if you have a component fail that spreads metalic debris that suspends in the fluid and clogs the filter. Lots of times the metal particles are tiny enough to flow through the filter and stay suspended in the fluid which is bad for all other moving parts.
The reason transmissions can fail if the fluid is changed at a higher mileage is simply because the worn off friction material is tiny enough to flow through the filter and stays suspended in the filter, adding to the viscosity of the fluid which adds hydrolic pressure, as well as adding to the friction between the plates. When you change all that fluid with fresh new fluid the extra friction/grip in the plates is gone and replaced with fresh slick fluid as well as slightly lower hydrolic pressures pushing against the plates... which all adds up to cause slippage, thus transmission failure needing rebuilding.
There is no proof or solid documentation depicting this because each and every transmission will be an individual case of wear and other variables due to the use and driving styles of different people. If you are considering whether or not to change your transmission fluid I would strongly suggest taking a small sample of about half a pint or so to inspect. You can look at it stirring it under bright light to inspect for presence of worn metal components. (will look like metal flake in a paint job) Same for presence of clutch material. (dull gray material, like graphite powder) as well as smell the fluid to see if it smells like tranny fluid (kind of a gear oil smell in BMW's case with the lifetime fluid) or if it smells burnt from overheating/overworking.
Basically you should look at the fluid in each individual case and get as many facts as possible from the fluid in each particular case to get a better idea, and thus make a judgment call from knowledge, not blind beliefs.
my 0.2c over
