There are many reasons why you would create classes for your inventory in RetailEdge. Classes allow you to get additional resolution on your inventory and sales information. For instance if you are selling clothing, you might also have some classes for belts and scarves. Classes in RetailEdge are most commonly treated as sub-departments. However, classes are independent of the departments. So you might have a class Men's and Women's and you can assign these to each item even if the items are in different departments. This way you can essentially flip your inventory and see sales and inventory information for the entire class or mens and womens even though it spans multiple departments.
One other very important reason you might want to create classes is for tax reasons. RetailEdge has the ability to create tax exemptions for classes and departments. Many States have tax exemptions for clothing. In the above example though you might want to track sales of your clothing by scarves and belts. If your State does not require that you charge tax on clothing, then you can create a class for clothing and then setup your tax juridictions to charge no tax on items that are in the clothing class. But you can still keep your scarves and belts department to give you the reporting resolution you need. Additional discussion about this can be found at
http://www.retailedge.com/phpBB/viewtop ... 676&p=2072.