i got 60K miles on my NGK 4 prong spark plugs

just a darkening no them. not that black.
no pitting.

should i replace them ?

one thing i gotta say i went to the stealer
and saw the Bosch replacement plugs for the car.
wanted 31 bucks.
they are Bosch and i dont like that the center electrode is the size of
a pinhead.
seems anything gets on that and u have a problem.

but those are what BMW puts in there.
im glad i get the NGK years ago but i must
say i never remembeer the originals on my 328i looking like these Bosch