On the project level, Microsoft Project helps you maintain a balance among scope, resources, and time: Have more tasks been added to your project but not more time? A quick look at your Microsoft Project schedule shows you if existing resources have enough free time to accomplish the new tasks, without extending the project deadline.
On the task level, Microsoft Project helps you maintain a balance between the hours it takes to complete a task, the assigned resources, and the overall task length. For example, if a task that takes one person 4 days to complete needs to be done in 2 days, Microsoft Project makes it easy to assign a second person.