Best known for his titanic five-novels-in-one omnibus 2666, Chilean writer Roberto Bolaño was prolific enough that even after his death in 2003, his bibliography continues to grow.
In “Advice on the Art of Writing Short Stories,” he suggested one reason for that prodigious output. Never stick to just one piece at a time:
Never approach short stories one at a time. If one approaches short stories one at a time, one can quite honestly be writing the same short story until the day one dies.
Of course, Bolaño also warns to be careful:
The temptation to write short stories two at a time is just as dangerous as attempting to write them one at a time.
But it seems clear which approach he followed.