Touareg transmission Fluid change on 2006 Volkswagen Touareg

Volkswagen indicates that the transmission is a sealed unit and does not require a fluid change. At what milage should the fluid be changed

Asked by for the 2006 Volkswagen Touareg
A lot of car manufacturers went to these "sealed for life transmissions" and found out "life" was 80,000 miles. At the time a car range we work on the oil was $80 a quart retail and the dealer didn't stock it, now is $10 a quart because they see it should be changed.
I would change it every 30K especially if you tow or drive off road certainly every 60K. at a minimum.