I weigh daily (in the morning) - how else would I know if what I'm doing (calorie intake wise / exercise wise) is actually working. It helped me learn about how my body loses weight most effectively - I found out heaps by making small adjustments based on those numbers.

I'm a personal trainer / fitness instructor too, and it goes against pretty much all of the literature out there, I know.

BUT, if I didn't weigh daily, I doubt I would have lost the amount of weight I did in the time I did, and healthily!