Enjoy 75,000 miles worth of yearly analysis reports from my 2010 Vibe 1.8 with the Toyota U341E four-speed.
I bought the Vibe from Carmax at 29,000 miles, and changed the ATF soon after. What came out was the worst looking fluid I've ever seen, although it didn't smell burnt. I drained the pan again at the next oil change and sent in a sample (second report below). That started me changing about twice yearly and sampling once yearly to track the aluminum. I scaled back to once per year since 8/14, and actually skipped 2017.
The two most recent changes used Maxlife synthetic multi-vehicle, and the rest were Toyota WS. Pan drains take 2.5-2.7 quarts. A filter change at 40,000 took 3 quarts.
I don't know if this is a bad example or what. I'm not the regular driver, but have never noticed any strange noise or behavior from the trans.
Here's a picture of the first change. It shows the engine oil look, but doesn't capture the creamy gray feature of the factory fluid.