in my experience, it's always wrong when I think it's right, and right when I think it's wrong. just like "which rook should go on the open file".
there's probably a theory answer for this exact position in db, but generally speaking I always screw up these kinds of moves. but I've heard many times about kramnik and other russian players "having worked over and over these kinds of situations", but it's never mentioned WHAT they actually worked on. I've assumed it's a "russian school of chess" thing, but I'd love to get my hands on the actual training material. anybody have anything on that?