Despite the differences that make every project unique, Project gives you several ways to reuse project work you've done before. Here are just a few examples:
Save time. Past projects make great starting points for new projects. You've already figured out many of the tasks you need, so why not use them to jump-start new projects? A Project template can contain tasks with task dependencies, typical durations, and even resources. Keep anything that stays the same, and change only what's different.
Standardize. Quite often, you learn the hard way what works and what doesn't. You can improve your results by basing new projects on your previous successes, not your past mistakes. In fact, by creating templates that reflect your organization's project management knowledge, everyone can benefit from the lessons learned on each and every project. You can use Project templates to define the standards that your organization follows. A template can act like a checklist with project management tasks that are part of every project, or contain the views, reports, and customized performance measures that your organization uses to evaluate project status.
In fact, the global template (Storing Project Settings and Elements) stores Project program settings that apply to every project. You can make customized elements available to every new project you create, by storing them in the global template.
Learn from others. You don't have to learn everything from the school of ...