My Fair Lady had a damaged negative, many dupe shots and no main titles. Vertigo had a faded original negative, no magnetic elements with exception of music which was stereo but had full vinegar syndrome. Some music elements lost on attempt at first preservation. There are so many films that need help, but there's only so much Harris and company can undertake. On a major restoration we spend several months in research and pulling together surviving elements.
Physical restoration can take well over a year.
Vertigo almost 18 months. My partner in crime is Jim Katz who runs the LA side. Research is done on both coasts. All elements are examined on west coast. A number of people have served as LA assistants, most recently Michael Hyatt, followed by Marlene Noble.