I was changing the air filter yesterday so decided to have a look at the NS bank of spark plugs. I.e. not needing to remove the manifold.
Came out relatively easily with no signs of corrosion or seizure and in excellent condition with no tip erosion at about 53 thou gap and a lovely light / mid brown colouring.
This is after 30,000 miles so just put them back in

Standard plugs....Motorcraft AGSF32N
PS..... 3.0L engine