Mike,
If you are fishing for one of the toothy fishies, a shock tippet is in order.
Other fish have sharp gill covers, or a habit of tring to rub the hook out of their mouths.
I use about 4" of wire for blues or pike.
Fish with some serious choppers.
For other fish that I might be concerned with I would most likely use a straight piece of 20# mono for a leader.
Your own mileage may vary.

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"The day after tomorrow is the third day of the rest of your life"