Turning basement into ADU, best practices for breaker box, furnace, water heater

[Greg Lovern]

When turning basements into ADUs, and the breaker box, furnace, and water heater are down there, what are best practices for handling them? Should they be made into a small common area that the main unit also has access to? Or is it okay to just make them part of the ADU that the main unit does not have direct access to?