How often to weigh in?

That's the way I do it as well.

I typically weigh every day. I go by a moving average, sort of. Essentially if I stay at a certain solid number or below for a few days, I lost a pound. For example if I weigh in one day at 156.9, and then the next few days are 157.5, 157.3, 157.4... I don't consider myself to be down to 157 yet. I have to weigh in consistently at or below 157 to log it in MFP as a loss.

That may drive people insane, but it works for me.

I weigh every day, because when I weighed only once a week before, I let myself slide a lot more, nutrition-wise.
That being said, when I weigh, if I've lost from the previous weight, I'll count it. I won't count it again until it's lower than that.
So, really, I only "weigh in" to MFP about once, MAYBE twice a week. So it averages out.

Makes sense in my head at least.

Personally, I can understand your fears of overanalyzing if you weigh in too frequently, but I do weigh in daily. Every morning, after I go to the bathroom, after I walk the dogs, as I'm feeding them I hop on the scale. I'm still usually in my pajamas. I weigh in everyday, because I'd rather see the strange fluctuations. I know that if I see a pound+ fluctuation, there is no need to freak out, it is just my body holding on to more or less water or what have you. However, weighing in daily I feel keeps me more accountable, and I see the bigger picture and trend on my graphs, rather than going a week and seeing no change, just because I was on a low day the first time and a high day the second time, or something along those lines.

I weigh in once a month for a few reasons. One is that, like you, I don't want to obsess over tiny ups and downs. I want to focus on eating and exercising and developing good habits, not on a number on the scale. Secondly, my scale is not digital, so I can't tell tenths of a pound anyway. Third, I thought it would be a good idea to weigh on the same day of my cycle every month, so bloating and hormonal weight fluctuations don't throw me off.

Yeah that makes sense. And referring to your third reason I usually just skip that week, because when I do weigh myself it's kind of all over the place because of bloating and what not.

I do two times a week, Sunday and Wednesday. I do it of a morning after restroom.

I make it a point to weigh most days when i first get up (after using the bathroom). Yesterday, for instance, it slipped my mind, but for the first time I didn't find myself driven to distraction from not weighing. Last night, I weighed myself out of curiosity, and the number was good, so I knew when I weighed in today that the number would be the same or less. Since it was less today, I will track the loss after tomorrow if it stays at the same number or below.

On the flip side, my friend is obsessive about weighing multiple times a day, but this allowed her to realize that she was retaining a LOT of water and needed to see her doctor. Then she was able to tell that the first diuretic wasn't working and that she needed to see him again. She also only records once a week.

My rambling point is, (IMO) weighing in practices are as personal as your weight-loss plan. Hopefully the fact that you know you are obsessive means you can figure out something that will work for you without feeding that obsession. Best of luck!

The 15th of each month

I weigh myself daily also. It's convenient and easy because my scale is right outside of the shower so I can weigh myself in the buff and then hop in the shower. I realize weight fluctuates so I don't freak out if I'm .6lbs up and I don't throw myself a party if I'm a little bit down. I've found that my weight bounces from day to day but I can count it when the fluctuation is consistently down. (um, did that make any friggin sense???)

And like someone else said, I actually find it somewhat interesting.