This is an extremely debateable topic, but the best answer is whatever works personally for you! I'm an every day weigher. I just have to know.
I used to see a lot of recommendations against that, but reading the Maintainers threads, it looks like many of the maintainers are/were daily weighers.
Here are two things I have learned about me:
I did weigh monthly, but if weigh day just happened to be a water retention day for me, I'd be very discouraged. Ditto, for not as big of a loss as I wanted - it was easy for me to throw away a month's work in the garbage because the scale lies
If I'm staying on plan, I look forward to daily weighing. If I am not looking forward to the scale, I stop and take a close look at what I did in the past 24 hours or so. It tends to keep me honest.