I can see from your reply that you have encountered these issues before and worked out solutions to your satisfaction. My situation is that I am converting a Foxpro DOS app to VFP. It deals with used car dealerships. When a car is sold there are any number of types of deals that can be worked out- these I will all subclass so that the individual code is easier to work with than the present jumble of cases and if statements that I have. This will allow me to easily create new classes of customers without in any way infringing on the behavior of present customer classes. On the other hand, once a customer is in the system the tracking of accounts receivable and the creation of reports again becomes very complicated. My idea is to have 1 set of classes to handle the sales end and another parallel set to handle the follow up activities. The only reason to split it up that I can see is just have smaller less complex classes. I already know what the behavior of the present classes will be, the problem is extracting it from the DOS code. Life is hell right now, but if I ever get this done I will have far fewer problems down the road.