At what point does a vigilant maintenance schedule become a detriment to the environment?

The Haynes Manual suggests atf change every 60k stating that it is not a"normal service" requirement unless a problem is indicated. I just changed mine last week(flushing 13 quarts of atf through the system) after 25-30k and only a slight amount of brown color was noted. I do a lot of stop and go also.

I suspect frequent changes of atf are like changing your motor oil at 3k intervals---admirable, but not necessary. The volvo manual suggest a 7k iterval, 3k is too often, 5k is about right.

The personal cost saving and lessening the need for unnecessary atf recycling should figure into your calculation given that there is probably no detriment to your transmission's longevity.

Dan