Is it the hybrid or the gas engine model? The hybrid has a CVT while the I4 and V6 have a conventional 6-speed automatic.
These have "lifetime fluid" although I replaced my '12's WS at a dealer at 60k just for peace of mind. As another data point, our '10 Sienna (also with "lifetime fluid") hasn't seen any trans service whatsoever in its 225k miles, and still shifts quite well - no issues with it, and I have no qualms about having followed the book on (not) changing it. I just happened to do the Camry's to make myself feel better, but it's probably not necessary.