See more InfoPath demos at http://office.microsoft.com/en-us/help/FX100485311033.aspx
If you design form templates, reusable template parts can keep you from having to reinvent the wheel each time you create a new form template. For example, many of the forms that your company uses probably include boxes for collecting contact information from the person filling out the form. For consistency, your company wants these boxes to be the same across all its forms.