The per square foot method is real and used as a minimum number of general circuits in a home.
There are also rules of thumb, they are not in the NEC and vary by place and electrician. For example a rule of thumb for me is 10- 12 outlets per circuit, lights seperate from outlets ect but nowhere is this specific in the code, its simply a preference to make it easier.
There are also rules of thumb, they are not in the NEC and vary by place and electrician. For example a rule of thumb for me is 10- 12 outlets per circuit, lights seperate from outlets ect but nowhere is this specific in the code, its simply a preference to make it easier.