Weeklies are there to make the program more livable. You can experiment with them to see what works for you. How often we weigh is dependent on the individual. Our weight fluctuates all day long. It can go up when we do everything right and down when we overeat. Hormones, too much sodium, too many carbs, sore muscles from exercise and many more factors can effect the scale. If the daily fluctuations dont bother a person, then weighing daily may be good. If watching the scale goes up makes you want to give up or emotionally eat, then once a week might be better.