Creating Setting dashboard for dynamic data controlling

Dear All,

I want to design a setting dashboard for dynamically controlling the data through the dashboard user, here is an example to narrowing the Idea:

- Creating TextBox (or more) Determining a period in (days) to consider the customer if he is active or not if the customer submit last order  within a certain period, for example, the dashboard user put (30) days in the text box as a maximum period to consider a customer active if he submits order within the last 30 days. How can I do measure check the text box if it is <=30 active otherwise not active? 

On the other hand, the page related to this setting must be aware enough to any changes in the setting dashboard.

Regards ,