I got to over 350 pounds while avoiding the scaled and I vowed I will never make that mistake again! Unless I am traveling, I weigh every day. The small fluctuations don't bother me, but if I see an upward fluctuation of three pounds or more it usually indicates that I am doing something wrong -- probably some hidden carbs or calories I was not aware of.

Different things work for different people, so I don't think there is one right answer to this question. Some people are really bothered if they get on the scale and it is up a pound or two from the previous day. If that is true of you, then weighing less frequently is probably better.