In most cases, setting a baseline makes your project plan as useful as possible, because the baseline enables you to track and adjust your project. But in certain situations a baseline isn’t very useful. For instance, if your project has so few tasks and resources that you can track progress in your head, you wouldn’t need a baseline. Or, if your project duration is very short, you might have little time or need to track tasks.
Of course, you can set a baseline for a project of any size and duration. If you want to keep an accurate account of how closely each project follows its original plan, or you want to use data from one project to help you plan future projects, you may find it helpful to set a baseline for each project.