When I am faithfully sticking to a plan and losing weight, I weigh every day, add the numbers at the end of 7 days and take the average; that's my WEEKLY weigh in that I record on my signature. I learned this years ago reading the Heller's books. I think it gives a more accurate picture. I don't get upset if the number goes up or down by .2 or something. I also don't get crushed if that ONCE a week weigh in is slightly up.