[vettestr]

No need to replace unless you just want too but make sure engine is cold. Use a plug socket if possible and the better leverage the easier if that tight. Give her the old LEFTIE LOOSIE on a straight pull. Try other plugs to make sure all is well before going for broke on 1 hole.
I always insist on anti-seize on the plug threads and a bit on the gasket. On aluminum heads it is mandatory in my shop and always remove when cold or cool if possible.