Our firm did a church several years ago, using Revit. It's a 2003 job number, and CD's were completed in Revit in 2005. That was probably back on version 7.1, MAYBE 8. From what I can recall, that file was a huge mess at the end. Thousands of reference planes everywhere, something like 50+ levels in just a 3 story building. Lots of "shortcuts" and things not modeled correctly. It was absolutely insane.
Now we're starting a new building project on the same church, adding on to what's already there.
What are the suggestions for this new project? Just go with the original Revit file, add a new phase and maybe some scope boxes and run with it? Try to clean up some stuff? Or maybe just copy model elements into a new file? I'm wondering if deleting levels will delete any model elements. I'm about to try it.