Bryon Spurlock has written a great article on why you should monitor Lync Server 2013. Byron makes a great case for monitoring especially for a Enterprise Voice Deployment. Old hands with Lync (and OCS) will not be surprised with the conclusions that you SHOULD monitor your environment, if only to know what is actually happening in your deployment.
A great feature of Lync Server 2013 is that monitoring no longer requires an extra server as was the case with earlier versions of the Lync product. Now, monitoring is co-located with the Front End Server. If you start co-locating roles on the front end (e.g. monitoring, group chat, mediation server), the hardware requirements for that box grow and so do re-boot times. But that’s a small price to pay to have significantly fewer computers to patch, manage and maintain.
To some degree, Byron concludes, the question is more: why NOT monitor!