Who has changed their transmission fluid?

I am a bad person. 2018 CX-9, nearing 160,000 km. Never had new transmission fluid. Never had rear wheel AWD “differential” fluid changed. Am I in “now or never” territory? I’ve read doing it/them at higher mileage is inviting problems. Should I leave well enough alone?
I've got a 2018 CX 9 with approx 154K. I changed the PTU and rear diff fluids at 150K - and plan to change every 50K going forward. Super easy to do. I will be doing a drain and fill on the trans next week. No filter change. My belief is that if the component is working properly then changing the fluid shouldn't do any harm but never changing that fluid is asking for issues. I don't believe in the lifetime fluid theory.
 
Did a oil test on my cx 5 at 80k. They say it's would be good for 30-40k more. So I guess Mazda "Lifetime" atf is good stuff. I used that data and did my cx 9 at 100k. Thinking my next one would be at 170k? Then we see how much longer car last.
 

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