Relational connection to ECC6

I wonder if anyone can help with two questions on connecting Business Objects to ECC6

1. I know how to create a connection and use it to build a universe from a SAP Query or Infoset . What I can't find any information about is do I need to create a new connection for each new project or can I just create one and use it in all my projects . What happens when reports are run against different universes using the same connection .
2. So far I have used my log on and password to create connections but these fail when my password expires what is the best practice regarding user accounts for creating connections from BO  to ECC6 .