I weigh myself every morning at 7:30am, before i've eaten or had anything to drink. And after i've used the restroom. :) I find that weighing in daily keeps me motivated and on track,

My son not obese but weighs himself daily. I was trying weekly.

ONCE A MONTH

It actually doesn't matter how often one weighs themselves. But important to keep an open mind. Understanding that one needs to realize that weight is always fluctuating due to many body changes going on. Water retention, digestion, metabolism, et. Meaning you often weigh different in the morning than you will in late evening. May change from day to day. A bit up and down. To get a realistic comparison for how one is doing weight wise is to select one day of the week and same time of day, to compare weight numbers. Examples choose a Saturday at around 9 AM. I kept track on a calendar by writing my weight on it at that day and time. Best to weigh without any clothing, or just in undies to be more accurate each time. It really doesn't hurt how often one weighs, just compare only from week to week (same day each week) for more accurate calculations. If in a weeks' time you weigh more than that same day a week ago, you need to make some adjustments to your eating plan. Get more exercise, etc. But if you weigh less the following week, then you know you are doing well.

I get weighed at my doctor's office only it's every 4 to 6 months but I usually go by how my clothes fit if I gain or lose weight