Nearly daily. I've found that daily weigh ins provide a lot of feedback. I know if I have inflammation from a workout (because I'll pack on 2-3 lbs overnight) or if I ate too many carbs (same). But when I see weight loss and I see the same number several days in a row, I also know it's real and not merely dehydration.
I've always weighed myself daily. I've heard of course that once a week is a better choice - I do it daily to see patterns of what affects me and how it can affect water retention and such - that way if my weekly weigh in happens to be on a bad bloat day I don't feel discouraged. As long as the overall trend is down, I know I'm doing the right thing. I might touch on a new low one day... then the next day the scale bounces back up and so on... but as long as it doesn't keep going back to my original weight, i'm moving in the right direction. Its always exciting to see that first new "low" number for the first time.
I weigh myself almost every day. It's (usually) the reality I need to start my day, otherwise I totally kid myself. It probably isn't a healthy habit.
I think that really depends on how it makes you feel and if it motivates you or makes you feel stressed / neurotic? I weighed daily for ages. Never bothered me if my water weight fluctuated day to day. It just helped me to start the day on the right foot.
I am also a serial daily weigh in type person. I started a new program at the beginning of June and have lost half a stone. There were definitely fluctuations and plateaus, but it’s handy to see it graphed out and the overall trend going downwards. It also keeps me honest.
I also weigh in every day, because I'm a graph person and more data is better for me. But I also track the week over week trends, every Sunday and that is the number I actually pay attention to. So far, in 30 weeks, I've only had a 0.0 once and a gain once (both of those during the plateau I was stuck in for the last 6 weeks). Not bad. So I do weigh in daily, but I don't obsess over the fluctuations