I don't believe in going too long without a weigh and measure. If you go a month and then when you do weigh in and you don't like what you see, it can be really discouraging. At least if you do weekly weigh ins you can make adjustments to the plan if needed to more quickly respond if things aren't working. If you don't want to do a weekly weigh in then I would at the very least do a weekly set of measurements. Of course you need to do what works for you. I would just hate to see you give up if you don't see the numbers you think you should be seeing after a long period between weigh ins. Whatever you choose, good luck!!