I weigh daily, but if I were weighing weekly ...
I wouldn't do anything that would make the scale temporarily lower. The resulting result wouldn't feel good like a "real" result would.
I *would* make sure not to do anything to make it temporarily higher - like eating out, training very hard, not getting enough sleep. I might put my legs up for 20 minutes to help make sure I'm not retaining fluid.
But, I've found that I can't always time those things just right. Sometimes the salt effect takes a few days to show up, sometimes it's the next day, same with other things that make me retain or drop water.

I guess I'm now comfortable enough in knowing that what I'm doing is working well enough, and all the fluctuations are motivating as well as intriguing... when I go up two pounds I can recognize that it's because I ate a lb of carrots while snacking and drank a ton of water, and that it'll all come out soon enough 