This book describes techniques for estimating development time and using those estimates to create schedules. This book also distinguishes between an estimate, which reflects the time required to implement a feature, and a schedule, which reflects how you fulfill that feature. Estimates are commonly expressed in eight hour work days. When creating schedules from estimates, consider dependencies such as the completion of a project before another can begin. Also consider daily tasks that take away from project time, such as meetings, support for existing projects, and so on.