There is always the "danger" that once you start on this conversion process, you’ll soon realize that with a little more up-front effort, you can create a generic data entry program or at least a template that can be used with an array of field data, a set of prompts (or screen layout), a set of field-entry routines, and some standardized file i/o logic to replace dozens of existing custom programs. The first one of these is hard to write, but after that, you may be able to convert significant chunks of your application quite easily.
An added payback for the effort involved is that you will have achieved a high degree of separation between your user interface, data, and business logic. But it is important to note that the arguments for doing a more thorough overhaul of your software should be based on the merits of better structure, easier maintenance, etc., since it is not strictly needed just to achieve the GUI interface.
