sparkplugs on E 350 5,4 liter engine
 

My motorhome is powered by Ford E 350 5,4 l V-8 engine, year 2003.
Mileage is 37 000 miles.
I've heard that on this engine sparkplugs can sometimes be "bonded" in the block engine after a while.
Considering that it is 10 years old, would you recommend to change sparkplugs sooner than usual to prevent this problem?

If the vehicle has stayed outside,definitely !
Never hurts to change them earlier. Make sure you blow the junk out of the holes before you remove the plugs. It wouldn't hurt to consider having an extra coil or two on hand because the original ones start acting up around 50k miles sometimes earlier.
I know it has only 37k on it , but time takes its toll. How does the belt look, might consider that too.

Thank you Hanky.
I'll have to check the belt.
Would it be a good thing to put WD-40 before working on the sparkplugs ?

A little WD-40 shouldn't hurt at all. Try to be careful when removing the coils and twist the coil boots gently before removing them so as not to tear any of them because when once torn that provides a path for the spark to get to ground. Suggest you use Motorcraft plugs and dielectric grease on the coil boots when reinstalling them on the plugs. If you take your time it's not a bad job. Also make sure to check the gap and set them to the spec in the owner's manual. The brake rotors can get pretty rusty when not used much so make sure to check them and make sure the calipers are free to move. If you haven't had to replace pads you just might be due for a set. Fords have no squealers to warn you when it's time to replace the pads and by the time you get any warning the rotors are shot . You probably already know all this stuff so I better stop here.