Isn't one day a week the same as 'consistently' on a weekly basis, really it is up to you and your commitments and how much progress you AIM to make each week. This question is as long as a piece of string, and the better question to ask perhaps is 'how many hours a week do you work on EE2 outside of class'. Whenever a question has a 'should' or high modality word in it, implies that there is only one right answer which can't be further from the truth. Anyways, all the best with EE2 (I haven't studied it before so can't give you advice on how long I took).