A “workaround” that people new to project management sometimes try is to manually enter start and finish dates for each task in the Entry table. This way, tasks start on the day the project manager assumes is correct. Although this approach might display what appears to be an accurate Gantt Chart, that chart is accurate only until project work begins.
When you begin to manually modify a task's start and finish dates, you prevent Office Project 2007 from doing what it was intended to do—create a project schedule based on tasks and their durations. Through this automatic scheduling, when a change occurs in one task, you can immediately see the domino-effect of change throughout the entire project schedule in the form of the new Change Highlighting and an updated Gantt Chart.
When the start and finish date fields have been manually overwritten, each time one task changes the project manager is forced to go through all affected tasks and enter new start and finish dates. Instead, you can utilize Office Project 2007's task relationships and constraints to define task start and finish dates without impeding the automatic scheduling of the software.