From my experience, every time someone mentions frequency of oil changes the standard answer is
"Nissan state 6000 miles, but most of us do it every 3000"
this is somewhat strange, because the Nissan Service checklist states a D1,D2 or D3 every 6k, with a D0 every 3k
D0 = oil change
maybe they do know what they are talking about.
however anyone going for the 6K changes may have problems.
PLEASE STICKY THIS! I THINK IT'S QUITE IMPORTANT