I just changed my CVT fluid myself today at just over 40,000 miles. The code per maintenance minder had not come up yet. The fluid drained out relatively clear, with minimal black residue (no metal shavings) on the drain plug. Refilled exactly the volume that drained out (4.2 quarts), easy DIY job! I'm definitely a soft driver and don't push the car at all but as has been recommended in previous posts, preventive maintenance is definitely cheaper than getting a new transmission put in later on.