One thing I have always done is weigh in the morning AND at night before I go to bed. Morning is for recording and tracking and night time is to see if I'm retaining fluid. If I'm puffed up from the day's meals, I know in a few days that will come on as weight gain. It helps identify which foods just are not OK in a way that only doing morning weighs doesn't. You have to be able to be neutral at the scale, though, and just see it as feedback. If little fluctuation will derail you, it's not a good idea.