I do weigh daily, first thing in the am. I too fluctuate within a range, so I enter it in a spreadsheet and plot my weekly averages. I only freak out if my average weekly weight goes above range, and then I know I need to cut back until its back down, or rather thats my plan although since I lost my weight that hasn't happened yet, but I do think when I have a week where I am at the high end of the range I intuitively cut back on things like alcohol and chocolate and then I come right back down to the low end of my range. I NEVER freak out if my weight is at the high end of my range for a single day, cuz I know its due to changes in fluid balance.

I too got into this habit when I was losing weight, cuz it was the only way to detect a slow but sure loss. But it does help me maintain my weight loss. Knowledge is power.