transmission flushes?

What do you think of transmission flushes or changing transmission fluid
more often than specified in owners masuals (usually 100,00 miles or never).
Think about it, some people do overkill by changing their engine oil every
3,000 miles, but they never even think about changing the automatic
transmission fluid. Yet the automatic transmission gets alot of use and has
alot of moving parts. It's the second most costly thing on the car to
replace next to the engine.

My parents cars never changed their transmission fluids except every
100,00 miles or so. And the transmissions usually died after 125,000 miles
or so. Imagine if people only changed their engine oil every 100,00 miles-
I don't think engines would last that long with dirty oil.

My car only has 33,000 miles. I'm planning on researching who does the
best job, what's the best technique, and have it done, or do it myself,
before 50,000 miles at least.

I know there is alot of BS and snake oil involved in the mainanence
business, often on customers who don't have a clue about cars. Some people
think transmission flushes are also a waste of money, likewise.