Trans fluid "flush" / exchange, or drop pan drain?

I know the Owner's Manual says to change the transmission fluid at 150,000 miles, but I also read/see a LOT of info suggesting making fluid changes at 30,000 or 50,000 miles instead. And then there's is the debate of flush vs. drop pan change. A Service Advisor at my local dealership told me something along the lines of "Ford has issued a notice to avoid dropping the pan if possible, and exchange fluid instead."

Of course, factors like towing and hauling weights and frequency are a huge...

Trans fluid "flush" / exchange, or drop pan drain?