I noticed that the following often required functionality seems to be rarely known:
As of SAP CRM 7.0 EHP 2 mandatory fields can be visually indicated in the following CRM WebClient UI applications:
Mandatory fields defined for a business partner role are marked, that is mandatory fields defined in Customizing for Cross-Application Components, under SAP Business Partner -> Business Partner -> Basic Settings -> Field Groupings -> Configure Field Attributes per BP Role.
For enabling this functionality you need to activate the business function CRM_TCI_1.
I would say reading the information related to this business function (documentation, release information) helps you to understand all details that you possibly need.