I carried out a Lync Server 2010 to Lync Server 2013 migration over the weekend and thought I would use one of the Microsoft guides as a baseline. Also to test if the information was sufficient.
It turns out, the guide from MS, http://technet.microsoft.com/en-us/library/jj205336.aspx, is a good starting point for step to step processing of migration. It applies to Lync Enterprise as well.
Most important is the process of removing all existing dependencies in Lync 2010 before the decommissioning process.
In the guide at http://technet.microsoft.com/en-us/library/jj205336.aspx. there are various references for all other workloads during the migration process. Such as http://go.microsoft.com/fwlink/p/?linkId=246227) for comprehensive, step-by-step instructions on decommissioning Lync 2010 pools. This link is in the migration phase 8 in the migration guide.