I weigh myself most mornings, nekkid, after peeing. Usually first thing after I get up. When I hit a rough stall, I won't do it every single day. I assess whether it is doing more harm than good and decide accordingly. But, I only "count" the weight that is on the anniversary of my surgery. I track all the weights in Baritastic, but the official weight in my weekly spreadsheet is Monday's weight (or Tuesday if I am out of town that weekend).
Every day is not for everyone, but I find it helps keep me on target. And, back in the olden days when I didn't weigh daily I would go off the deep end and then gain 10 lbs or whatever it would be. I'm not concerned about doing that now, but I'm trying to prepare myself for the long term and what I know helps keep me honest.
It's a very personal decision, since we are all wired differently.