I prefer daily weighing and there has been some research that suggests this is a better strategy for weight loss.
Once you've been weighing daily you can appreciate the random fluctuations and it makes weighing in less frustrating when there isn't a loss (or little gain). Hypothetically, say you are a weekly weigher and the day you decide to weigh in there is no loss even though you've been "good" all week. If you weigh daily, it could have been a fact that the trend for the week was down and there was a loss the day before. It might be coincidence that the day of the week you weighed in was a random fluctuation due to water retention or other factors.
Once again, to each his/ her own. Some people just get too upset and frustrated to see random weight fluctuations and they prefer to weigh weekly or even monthly. Try out different strategies and you will find something that works for you!