What levels is coaching no longer worth while?

[sweeng8]

Hi,

Just wondering what the opinin is on the levels that coaching is most useful for. For example, it seems obvious that people who cant beat microstakes need coaching, but if you cant beat say 2/4 would coaching still be useful? By 2/4 most would have a solid grasp of poker book knowledge but obviously far from the finished poker player. At this level is there anything that can be taught by coaches or does it have to be improvement through making your own mistakes? Would about if your limit is 5/10, 10/20,etc. when does coaching become obsolete?