DON"T DON"T start changing gaskets!!!!!!
If it's NOT BROKE don't touch it! Keep all oils in good shape and make sure Radiator and cooling system is working good and clean with good antifreeze. Plugs? Plugs last a long time now-a-days and the one I have pulled on any newer Ford engine even at 100,000 they look great as long as you have kept up on your matinace. FUEL FILTERS are very very important as they keep your gas clean BUT when ANY water or moister get in them they clog up FAST. They are very easy too change too...
The main thing is to NOT get it hot (OVERHEAT) and these engines are good for at least 300,000 miles easy!
I have way over 200,000 miles on mine and my neighbor has close to 260,000 on his too.