Refresh Test System with Prod Data

During a Windchill project, is it standard practice to refresh the Test system with Production data before testing major project phases?

If so, can the refresh be selective (e.g. Database and Vaults only), or must it include the entire application environment every time (e.g. WC Home Files, Apache, etc.)?

What is the standard approach: a full infrastructure-level server clone or an application-level refresh of the software components (e.g. Database and Vaults)?