I weigh myself every day first thing in the morning, but understand that my weight will fluctuate based on water retention, time of the month, etc.
A handy tool for tracking long-term weight trends is
https://www.fourmilab.ch/cgi-bin/HackDiet/ It smooths the daily weights statistically so you see trends rather than 'I ate salty popcorn and drank a gallon of water before bed'.