An inspection of the maintenance schedule of many Toyota vehicles reveals that there is a 100,000 km (60,000 miles) replacement interval if the vehicle is used on short trips, city driving, hauling heavy loads, trailer towing, or using a car-top hauler. Check your own maintenance schedule for your vehicle's requirements.
My maintenance manual states that transmission fluid should be changed at 60,000 miles for severe use, and if I recall correctly, it also says fluid should be inspected every 30,000 miles, although I may be confusing that point with a different situation.
That seems very typical, but some do claim "lifetime" which is nonsense. I'm taking a more assertive stance, given the high value and importance of a transmission, and with the Mityvac or drain plug working well on most of my vehicles, and the extremely low cost of transmission fluid, of doing it more frequent than recommended.