How Long Would It Take to Get Electrolysis Done All over the Body

When i said all over the body i literally ment it, so the stomach,back,chest,butt,legs,face...everything, how long would it take and how much would it cost on average? and how painful is it? i heard its the most painful way to remove hair and why do people prefer laser over electrolysis?: electrolysis is known as permanent hair removal whereas laser is only hair reduction? thx