In addition to volume pricing and simplified management, volume licensing offers benefits such as Software Assurance (SA). With SA, users receive all product updates during the term of their contract, so customers are always licensed for the latest version of the appropriate software, as well as for support, planning, training and IT tool services. SA is included in some programs and is an optional purchase from others. In the early 1990s, as LANs and WIDE Area Networks became more common, enterprise customers began to require some sort of licensing program for MS® software. Prior to this date, customers had to purchase multiple packages of finished products and keep proof of purchase for each unit. Developments such as virtualization, mobile devices, and cloud computing have forced MS® to change the terms of the license agreement. Many of these changes create transitional complications for existing customers and may require exceptions for certain products or regions. An Enterprise Agreement (EA) is a volume licensing agreement that provides the best value to an organization with more than 250 users/devices for public sector customers or 500 private sector users/devices. CAs offer a range of products that include software assurance, access to online services and subscriptions. Improving operational efficiency through access to unique technologies and licensing rights The simple fact that Microsoft® has so many products and sells them in virtually every country also adds to the complexity of the program. .