I work my horses to become responsive to leg and seat After they are solid on the bridle. That means I start to pick up the rein and they are softening up asking 'what do you need.'
I can and have done an entire reining pattern bridleless, however, the more time you spend not using the bridle the heavier the horse becomes to it. I teach that seat and leg are secondary as they can only be truelly reinforced with rein aids. Yet the goal is to never have to pick up on the rein and touch the bit.