It varies by model, I know some lower end EVs from GM still use the breaks quite often depending on the driving mode.
They are active in reverse, to ensure that they are used and so that any rust gets cleared from the rotors. They also activate if you slam on the brakes or if the battery is at 100% charge and the kinetic energy can not be used.
I have about 12,000 miles on the car over the last year and the rotors and pads look the same as when I got them. The first annual inspection showed no measurable wear.