I think it's different for everyone.
Some people like to weigh themselves every day, even twice a day or more. Other people get too stressed out by the daily fluctuations for that, and weigh themselves about once a week.
As for me, my "official" weigh in is on Friday morning. But I also like to weigh myself once during the week as well, usually on Wednesday, just to see how things are progressing.
And sometimes I will weigh myself on Monday, too, to assess the damage if I've had a binge-filled weekend.
