The first time I seriously lost weight (about 20kg) I didn't start out trying to lose weight really
I started going to the gym to strengthen my back muscles (had a really dodgy back). Then I just thought I might start eating healthy. Because I wasn't specifically trying to lose weight I didn't get on the scales AT ALL. I eventually had to weigh myself for the annual ski trip with my school (months after joining the gym). When I hopped on the scales I took one look and told them their scales were broken lol. I was 8kg lighter than the year before!!! After that I didn't weigh again for about a month.
It was so motivating to see a really big loss. Towards the end of my weight loss I started weighing every week, but I didn't see any movement most weeks. That was really depressing for me.
Anyways, the point of all that is that maybe for some people once a week is still too often to weigh. If you are losing large amounts of weight each week, once a week can be good. But if you are only losing 0.3 or so per week (I am usually a slow poke when it comes to losing weight) it can be disapointing. It just depends on you... but I definitely wouldn't weigh every day, there are too many factors that could affect it.
Sorry for the long post... I know I'm rambling....