i'll remove some stuff earlier to water easily, but not if it is a large portion of what the plant currently has to soak up light.
I like to do this 1 time, beside some minor cleanup of lower leaves for watering reasons along the way. So, i do it about 2 weeks into bloom. Not much will grow back underneath with little light causing leaf growth. Same time i defoliate. at 14 days into 12-12, there's still 7-10+ days of growth - depending on plant of course and familiarity with a clone or strain helps immensely.