>I think the only thing I really have a problem with is the FUD that claims once you leave VFP there is no more data handling, oop, RAD etc.
>
>Can you provide examples where best practice routinely involves changes of parent class? Why would you plan this way rather than (say) using (NET) interfaces? Serious question.

I'd turn that around. If using class inheritance is an option why would you opt for an interface?
On the same basis, if you have the ability to easily insert classes into an existing hierarchy where that is the best solution why would it not be best practice to do so......