Show-Hide actions will cause fields to display or disappear based on the ticket-buyer's selection. This video will show you how they work.  

Note: The action will automatically assume the opposite is true. 

For example, if you tell an option to show based on a certain condition, it will automatically hide the rest of the time. 

As ticket buyers purchase tickets, deleting a ticket level will delete your ticket buyer information tied to that field. Instead of deleting, hide the field or ticket level so you can still access the information as needed.

Here is how:

Create an action to hide a ticket level after today's date.