This chapter explains the importance of fully defining your performance and scalability goals. It helps you to identify what you need to accomplish, showing how to set concrete and attainable goals. This chapter also explains why it's important to maintain historical performance logs, and discusses numerous technologies and services that are available to aide in this effort. It stresses the importance of making regular backups, and of testing backups before changes are made. Finally, this chapter describes best practices for testing changes, and deploying tested changes onto production servers.