'A consistent body of work'
In the world of the artist, collectors have tendency to get an artist's piece. They really like it, and they get another. If the two have some similarities that 'tie' them together it is deemed more desireable. Think of the encyclopedia britanica, you don't just get the 'G' volume. You get the entire collection.
Many artists, produce a series of 5 -20 pieces that may contain a theme. Once they've done that, they can move on to another piece. An artistic 'one off' is really the artist trying something new, if he/she likes it, they will produce a series out of it.
May all your turnings be smooth,
Brodie Brickey