I just replaced mine at 110k on our 2007 Edge. I was starting to see a decline in fuel economy. The plug swap is not hard. The only cursing happened when disconnecting the vacuum lines behind the plenum. I used OEM plugs. Fuel economy seems to be back to normal. I also swapped my plenum gaskets. I measured the old gaskets. They were 1mm thinner than the new ones, so they had taken a set. For $35, I bought OEM from the dealer. The next owner gets to do the next swap.
On another note, I say the Edge has done really well. We have only swapped, plugs, brake pads, turned rotors twice, battery, sway bar bushings, seat switch and oil changes every 3k since 18k when we bought it.
