Only1, if you search the forum for "weigh" or "scale," I think you'll find many, many threads on this subject. It's a pretty popular one!
I usually weigh in every morning. I think it helps keep me on track. However, my nutritionist and psychi have other ideas. They think I'm fixating too much on the number, so they asked me to stop weighing altogether. I weigh in at the nutritionist's each week, but I can't see the number and he won't tell me. He says my body composition "looks good."
I don't know if they're right, but I'm willing to try it. In the meantime, not weighing certainly does bring up a lot of my emotions about eating and weight, so for that alone, it seems worth it.