The Lifewriting™ approach to your writing career demands a relatively high creative output. It isn't designed to coddle people who nurse a single story for years before sending it out.
But students often protest that they simply don't come up with many good ideas, and that the ideas they do generate are appropriate for novels. In my opinion, basic ideas have no intrinsic length. The TREATMENT of an idea has an intrinsic length. The Civil War can be treated in a one-page story, on in a library of books. It all depends on the skill and intent of the writer.