And beware of file complexity... connected networks kill productivity. Those are more commonly found in MEP than in AR or ST unless you have a lot of complex curtainwall or got too happy with the rebar tools. Plumbing is usually the first to get voted off the island. Their pipes are always calculating the connected network, and will blow up a model quickly, especially with more than 12 users in one model together. Then, Mechanical follows quickly. And, generally, Electrical doesn't want to play with others very much, so they jump off next. Everywhere I've worked, we've tried to be one happy family and end up splitting out on lines of Systems. Emphasis on Systems, not disciplines. That includes Shell vs. Core. But, never arbitrarily. Always based on complexity, size of the project, delivery methods, etc. As the industry is doing more and more IOT work (no, not Internet of Things, I'm talking about Initial Outfitting and Transition), we need all the FF&E to be in a Room or Space object and it needs to be phased. DoD work requires this, and requires program validation and equipment list validation, room by room. Keeping FF&E together with Interiors and all the planning Rooms is a necessity. Worksets are your friends in this, and I highly recommend getting everyone to practice selectively opening Worksets when they open their files to save time when they don't need to see the whole kit and kaboodle.