I am quite familiar with the practice of having all bath receptacles, in all baths, on one circuit, protected by a GFI receptacle in the first bath the cirrcuit reaches. "Economy" is always cited as a reason for this.
I question that reasoning.
Sure, it makes sense in tract homes of the "1970's" style. In those homes, the design usually had all the plumbing grouped together, so baths were either back-to-back or directly above one another.
Yet, I have just come from a new home in the "Courtyard" style. This style has the rooms arranged in a box, around an inner courtyard. There were five baths, including eight receptacles , scatttered around this square, and on two levels. One GFI receptacle protected them all.
That is a lot of wire to loop around, up, and down. Apart from the wire cost, there is the labor involved. Compare that to using a multi-wire branch circuit, with one leg for the neighboring room, and one for the bath- and each bath having its' own GFI.
Since, in realtive terms, the cost of GFI's has dropped- I think saving $$$$ by eliminating $10 devices is often false savings!
(This can also be another reason in favor of AFCI devices!)
