Safari Books Online is a digital library providing on-demand subscription access to thousands of learning resources.
Most organizations that implement Dynamics CRM (or any new CRM solution) begin with an initial period of heavy customization prior to the time that any users are actively updating records. During this initial phase of customization, it is perfectly acceptable to have only a single instance of Dynamics CRM available.
Most organizations tend to continue to customize Dynamics CRM after the initial rollout. During this process of continuous improvement, it is important to establish an environment (and procedures) for development and testing that mitigate the risk that your production environment is disrupted with unexpected changes.