It depends on the condition of your old wiring. Some say that the wiring breaks down (and the insulation) over time. I
think if the wiring is pliable,flexible and without alot of repairs, then use it. But if it is showing age and most importantly, you
can afford it, then replace it. Only buy new from M&H through Yearone, And then only when they are having their 30% off
sale. That is happening on a fairly regular basis lately.