National Electrical Code 2014 requires ground-fault protection for personnel in dwelling units for all 120 volt, single phase, 15 and 20 ampere receptacles installed in the following locations: - Bathrooms. - Garages - Accessory buildings with floors at or below grade that are not intended as habitable rooms. - Outdoors, except where receptacles on dedicated circuits are not readily accessible, and are used to supply snow-melting, deicing, or pipeline and vessel heating equipment. - Crawl spaces - Unfinished basements, unless the receptacle is on a dedicated circuit and used to supply a burglar alarm. - Kitchens where the receptacles serve coutertop surfaces. - Where a receptacle is within 6 ft. (1.8m) of sinks in other than kitchens. - Boathouses - Where receptacles are installed within 6 ft. (1.8m) of the outside edge of bathtub and shower stalls. - Laundry areas Arc-fault protection is required in dwelling units for all 120 volt, single phase, 15 and 20 ampere branch circuits supplying outlets and devices installed in: - Kitchens - Family rooms - Dining rooms - Living rooms - Parlors - Libraries - Dens - Bedrooms - Sunrooms - Recreation rooms - Closets - Hallways - Laundry areas - and all similar rooms and areas I don't know where you *shouldn't* install them, I only know where you are required and not required to. I guess you *shouldn't* install them anywhere they're not required, or you'd be wasting money?