The simple answer is to follow the owner's manual/factory recommendations, but sometimes IMO things aren't that simple.
I'm no conspiracy theory guy, but it's wise to remember that the manufacturer cares about you making to the end of the warranty period; they could care less if you make it to 200,000 miles or not.
I'm struggling with this issue on my XC90: Owner's manual says never touch the transmission fluid, yet driving in stop/go Phoenix heat 7 days a week has me really questioning if that's such a great idea (not doing an exchange, ever). Since it's an Aisin, I'm thinking of trying to get THEIR recommendation about servicing (or not servicing) the box.