When should arbitration mailboxes be moved?

Hi

I am in a complex exchange 2010 environment and exchange 2013 servers have just been installed.

When the arbitration mailboxes should get moved from 2010 to 2013?

A. Before?

B. During traffic cutover?

C. After cutover?

I saw the following but I don't know if anything else will stop working " If you don't move the arbitration mailbox, Exchange 2013 cmdlets that are run won't be logged in the administrator audit log and eDiscovery searches run on Exchange 2013 servers will be queued but won't start"