Since cars have gotten away from transmission fluid dipsticks, how can you tell if you have to change the fluid in a CVT? How hard is it to check if you need to change the CVT fluid because some CVTs out there don’t shift like normal automatics?
Change it by mileage. 30K miles is a good interval even if the manufacturer insists it is "lifetime" fluid.
If you’re planning to wait to change the fluid until you feel it malfunctioning, you’re waiting too long between changes.