Use a corded home phone whenever possible, to minimize the need for a cell phone. Cordless home phones emit RF, so replace cordless phones with corded home phones. One initial step is to unplug the electrical cord of the cordless phone base station when the phone is not in use, because otherwise that base station will emit RF nonstop. Note: you can plug a corded phone handset or corded headset into your VoIP connection.  
Over time, the number of cell phone calls per day, the length of each call, and the amount of time people use cell phones have increased. Because of changes in cell phone technology and increases in the number of base stations for transmitting wireless signals, the exposure from cell phone use—power output—has changed, mostly lowered, in many regions of the United States (1).