I weigh in twcie a week: Monday & Thursday.
I tried the everyday route and the once a week route. Pros & Cons with both. I find everyday makes me too anxioius. Once a week makes me lose touch of my goal.
If I weight myself on Monday I know if I'm on track or if I had way too many apple martinis during the weekend and need to adjust. By Thursday I know if 've been honest with myself and can tell if I'm on track or not.