I have only seen her wear the brown dress underneath the 'carpet/curtain' overcoat on one other occasion, which was for a reception in Greenland. I can't find the pic, but she wore a fancy hair clip with that. And the blue dress underneath the blue overcoat might have been worn in Australia, I am not sure. But, so far as I can remember, I have never seen the overcoats and the dress worn this year for any other occasion besides the New Year's Court.
I think its good that she recycles the dresses for New Year's Court. The dresses/overcoat combo is appropriate for these formal royal courts. This event happens once a year, where she needs a fully covered formal/sober dress. I think its also good from a PR point of view during this time of recession, Danish people will only look at recycling outfits positively. IMO, it would look odd if she were to buy new dresses for every occasion (she wore a new dress recently for the New Year's Banquet) in this time of global recession.