On my ‘11 superduty. Fords says 100K miles for fluid/filter. Nonsense says I.

Really haven’t had time nor the inclination to crawl around in the gravel to do it, so took it to local transamission shop. Pan was clean and fluid bright and clear @ 80K. Around 1/3 of that mileage is towing and some of it heavy. Happy with the result.

Good to hear. That's longer than I would've went. Can't say for sure without a fluid analysis, but it sounds like it could've gone to 100K.

Could not quite get to it earlier due to some reasons. But you’re right.

About a week after I had my transmission fluid changed, I heard one of those car guru shows on the radio that said not to do it unless it was discolored and giving problems. Follow up calls to the show had guys talking about their transmission slipping after they changed the fluid. No issues with mine so far, but it is in the back of my mind. The rational is that the particulate in the used transmission fluid helps the engagement. Now I don't know what to think?

My understanding is that applies to high mileage trans that haven’t been changed. If performed at ‘sensible’ intervals, it makes sense.

And never do a flush procedure.

The trans slipping after a fluid change is plausible, at least to me. Trans fluid is very specific these days. Using the wrong fluid that's not compatible with the glue used to bond the friction material on the friction plates could very well lead to slipping or a failed transmission. Personally, I wouldn't let any place change my transmission fluid unless I could personally verify the fluid they're using is what is called for by the manufacturer of my vehicle.

Local shop in a small town w a very good reputation. I watched most of what they did.

I trust them. They rebuilt my E4OD in my ‘93 which had no fluid service until it chit the bed.
I’ve learned a bit since then

I have always said, nothing suffered damage by changing the fluids early.

Late, well, thats another story.