Leverage Nested Policy Expression?

The burning question is when should a policy assertion author leverage nested policy expression?

When we talk about nested policy expression there is always two or more policy assertions involved. I would use the following two design questions to determine the possible use of nested policy expression:

• Are they designed for the same policy subject?
• Are they dependent?

If the answers are yes then leveraging nested policy expression is a good idea. However, there is one caveat: nested policy expression participates in the policy intersection algorithm.