The App will be sending you weigh-in reminders on days that you chose to weigh in when you initially created your diet. The last weigh-in of the week will trigger a weekly adjustment. More on adjustments here: How weekly reviews/adjustments work
We give the option of weighing in 2 – 5 days per week, as long as weigh in days fall on a weekday (m-f)
Research shows that weighing in multiple days per week (rather than 1, or even less frequently) is best for weight loss. One weigh-in provides less information because a single weight is influenced by so many (aforementioned) variables. Multiple weights are needed to establish a trend over time. This is essential for identifying adjustments that may need to be made to your plan to optimize your progress as you move from one week of your diet to the next.
You may change you weigh in days in the settings at any time: Settings; Changing weigh-in days, units, and disabling meal tracking