Education is key. This is overly simplified but the overall message is the same, no matter the source.

Most manufacturer guidelines are based on LAB testing which is highly controlled. 90% of the cars on the road should use the SEVERE service duty intervals for just that reason.

http://transmissionrepairguy.com/tra...n-overheating/

Unless you can guarantee that your fluid will never see above 175F and you drive like a granny 100% of the time, you need to change your fluid as needed.

Here in AZ, I can feel the difference between good fluid and stuff that's been cooked after a couple of 110F+ summers where my engine and trans operating temps easily exceed 210-215F. It is night and day as the old stuff will slip and will make my transmission feel like mush when it shifts. With fresh fluid, even the first summer, i get crisp shifts that will throw you back as the auto whips through the gears.

 

My Dad (Died in 2014 and I miss him dearly) Worked for Chrysler for years as the head mechanic then was the top mechanic (actual title Superintendent) for New York City Transit Authority (every mechanic reported to him). He taught me some things when I started driving in 1972 which I would like to share;
1.) Fluids of any kind break down and get contaminated over time, when it does it is not as effective anymore and this causes wear on the parts. Change the oil and filter every 3k (OK with today's engines I wait until the oil change light comes on)
2.) Change your transmission fluid every 60k (Ok with the new synthetics I moved this to 100k)
3.) Coolant at the manufactures recommendation
4.) Brake and power steering fluid every 10K ( moved this whenever I change pads or 60k whichever comes first)
5.) Wash it once a month try to rinse it every week
6.) Wax it twice a year.

Well every car I have had since 1989 has lasted over 300,000.00 miles on original engine and trans and still looked good when I got rid of them (except the 1993 Ford probe that was totaled with 260,00 miles on it)


Hope this helps

 

With all due respect to your inclination to extend your father's pm schedule, keeping it simple (and relatively conservative) has worked well for me very well, too.
I don't drive tons of miles but I annually rotate the 3 service items that most people put off or simply don't perform:
Year 1: Trans fluid; Year 2: Coolant flush; Year 3: Brake/Power Steering Flush Did I change plugs last year? If not, do it this year: Repeat... Has worked for me for decades; my car, my wife's car; each of the kid's cars.
I suppose if I actually drove 20,000 miles/year I would move to a 2 year schedule instead of 3 years ... But then again, I'm pretty conservative and do "the big stuff" myself once a year when I feel like I need to act like I can still turn a wrench =;^)
I just bought a 2005 V6 Mustang Premium w/103,000 miles (I guess that I'll have to add a diff lube change). It was obvious that none of the fluids mentioned above had ever been changed. What scared the hell out of me the most was the thought of changing the plugs... and I was right. They had never been changed and I was very fortunate that I didn't break at least two of them off in the head as they had been in that motor for almost 15 years. BTW they were still giving better than EPA estimated gas mileage! (Now that I think about it, changing plugs every 5 years might make more sense) NAH!