A friend (April 27 Taking a Stand) has started a conversation about work for exhibitions so thought I would add my tuppence worth (though it might come back to bite me in a few weeks time).
An exhibition piece should be an example of your best work, a very special work. An exhibition offers the opportunity to push the limits, push boundaries, try new techniques and colour combinations. It should be recently made but I don't have a problem with the same work being displayed multiple times so long as the audience will be different. For instance, in my present case, I imagine the audience at Tauranga Spinners and Weavers Exhibition will be quite different from those viewing my work at Inspirit Gallery, Hamilton. The work should be fun to create and look at, it should have creative magic or tell a story whether happy or tragic.
It should not be churned out with the purpose of filling a hall. An exhibition should allow space for each piece to be viewed with the appreciation it deserves. Every inch of every display board does not have to be filled. I know an artist who deliberately puts wide frames on her tapestries so they can't be crowded out.
A little self critiquing could help. Does this piece have wow factor, was it made with passion? The artist usually knows when they have made a really great work - that's the piece to submit for exhibition.