Every one is different, there's no one right answer. Lots of people have to weigh in only once a week (or even once a month) or they drive themselves crazy. The day-to-day fluctuations can wreak havoc with their moods and choices. And doing it every day makes them feel obsessed.
Me, I like to weigh every day. I think I would be more obsessed if I had to WAIT a week

. And seeing the daily fluctuations actually makes it easier, for me, to not freak out over scale numbers. Because I can see how it varies.
And I don't think, hmmm, l won't weigh for another 6 days, this little off plan choice won't hurt ...
Plus, daily weights give you a chance to correlate the things you eat with what you weigh (for example, water retention). And really, I just like having lots of data

.