Q: When should I use the Restrict Visibility by Date function on the Form Layout?
A: You ONLY need to use that function when you have an item on the Registration Form Layout that you want to show up for a limited period of time. A good example of when you want to use this feature is a late fee that you want to kick in 5 days before online registration closes.
You do NOT need to have the visibility of every item on the Registration Form Layout restricted by date if the items are available for the same time period registration is open. This creates issues and extra work when the event is cloned and the dates need to be updated.
You can find examples and more information in our help documentation found here.