Voltage Regulators:  An absolutely necessity in your recording, mixing or post production facilities.  There is power conditioning and varying degrees of protection.  But Voltage regulation has to do with keeping a constant voltage (in the U.S cases 120V) to all your equipment.  Keeping a constant voltage to your equipment is necessary for lengthening the life of it.  Voltage Regulators are perfect for home studio where things like HVAC, Washers, Dryers are constantly coming on and off.