I include my cell phone in the business use of home calculation with the idea that even if my parents normally just use the house phone to call me the phone is my security line in the event of an emergency such as when we are outside so it is available for use always during daycare hours. I include my cable and internet the same way with the idea it is available to us during the daycare hours to watch tv or do lesson planning during naptime. Again something that applies to us but not necessarily other businesses because it isn't part of how they conduct business.