It really depends upon the objective and the students.  For some objectives, most of the class will be able to progress through all stages on one day, but other objectives will take more time.  The important thing to remember about GRR is that teachers should not release responsibility to the students until they are have demonstrated some measure of mastery with the previous stage.  If the bulk of students are confused during the “We do” phase, the teacher should stop and reteach on the next day.  Students should engage in collaborative and independent work every day, but they might be working with review skills rather than the skill that was taught on that particular day.