header wrap or not?

It does lower the underhood temps nicely but it definetly shortens the life a bunch. I found that out the hard way. I put a very good quality set of headers (3/8 flanges and 14 gauge tubing) on my old Dakota pickup and wrapped them and they only lasted about 4 yrs./40,000 miles before they were complete junk. All cracked and rusted out. I'll never use it again.