I've registered screenplays with the WGA before submitting for festivals and competitions. How necessary is this? Also, when you register a screenplay and get a guild registration number, is it registering the exact script or overall concept? In other words, if I register a script with the WGA or other place and then make edits, introduce a new character, etc., is it still registered if the concept remains the same? What if I change the title of the movie after I register? Is that registration number still valid?