Agreed. If you open the drain plug, drain it. Put the plug back in. Fill it and then repeat this process 2 more times, that WOULD be crazy!!! I change it based on color and transmission response. When I first changed it, the transmission was slipping a bit and the fluid was reddish-brown. The fluid I put in was bright red. After a couple thousand miles, the fluid was much closer to red, but with a brown tint. Now, 50k miles later, I'm ready to do it again because the transmission is slipping a touch. I meant to do it in the Fall, but things happen (Winter and Xmas), so it's now on my Spring calendar... or Summer. Well, definitely by Fall.You are crazy if you drain and fill three times. All of you are crazy.
And THAT is the correct approach to trans fluid changes. Do it every so often. If you change your own oil, changing the fluid at the same time is easiest. You already have the tools out and are ready to go. You just need a clean drain pan and an empty jug to measure the fluid.