Windows Client differs from other Microsoft products because every new PC ships with a copy of it. Organizations need to analyze the benefits and unique content of Software Assurance for Windows Client to decide whether it's worth the annual fee. 

Microsoft has made a special effort to increase the value of Software Assurance (SA) beyond new version rights and to encourage the adoption of SA for Windows Client. Here, we present a framework to analyze and quantify the benefits to enable organizations to decide whether it's worth the annual fee.

Full Article