Our advice
MS Project 2007 and 2010: presentation

Each time a new display or custom field is created in the [Format], [Project] and then [Properties] tab, it is stored in the project file. In the [Organize] dialog box, files created for a project (in Global.MPT format) can be copied and used in projects to be created.

If you're using your version of MS Project for the first time, or after a long period of non-use, take the time to familiarize yourself with the menu and toolbars or the Ribbon before working on your project, and save your work regularly.