In many organisations, permissions are guarded carefully and are not given out lightly. Domain Administrator and Enterprise Administrator privileges are rarely given out to anyone. On the one hand, this is a good thing as it reduces the number of people who have all powerful user accounts and therefore reduces the risk of those with such powerful accounts doing damage (either accidentally or intentionally). ON the other hand, lack of privileges can make installing enterprise software packag4es, such as Lync Server 2013 more difficult.
In a recent blog article, Andrew Price, sets out how you can install Lync Server 2013 without Domain Admin permissions. As the first paragraph sets out, you DO need Admin rights on the Front end servers in order to carry out the installation, but that permission is local to the FE Server (and other key Lync Role servers including Mediation and Edge).
This article makes good reading for anyone planning on installing Lync Server 2013 and you work in a permission scarce environment.