In history, writers are remembered for typically quality or output, and very rarely, both.
We have writers out there who inflict hundreds of really bad books on the public, and by contrast, people who write only 1 book, but it's really, really good. So I'm not saying that how much you put out is any indication of how good you are, by any stretch of the imagination.
Every now and then, though, I like to remind myself how much you CAN get written in your lifetime when I think of the following authors:
Mystery writer Charles Harold St. John Hamilton (aka Frank Richards,
1876-1961) made it into the Guinness Book of World Records for producing more than 72 million words. (A typical single sheet of 8 x 11 paper is considered to have ca. 250 words, as a reminder for perspective.)
In Romance, we have Barbara Cartland (1901-2000) who penned over 700 novels in her storied lifetime. That's like, what, nearly 7 novels a year?
Among Westerns, Louis L'Amour (1908-1988) has at least 122 novels attributed to him.
Canadian horror writer Dan Ross (1912-1995) is known to have written at least 358 novels. This is an estimate, because he also wrote under a lot of pseudonyms, so the figure could be even higher. He also published more than 600 short stories. But it may interest you to know he didn't write his first novel until he was 49. So let's hear it for late bloomers.
British children's book author Enid Blyton (1897-1968) has more than 800 children's books and 10,000 short stories to her name. Her most famous creation is a series called Noddy, and she's apparently quite popular in the U.K., India, and Australia among other places.
Of course, we have to recognize Isaac Asimov (1920-1992), the Russian-born Jewish science fiction writer who is officially known to have written over 500 books and 1,600 essays, including several non-fiction works. Many of them thick-ones!
And finally, Agatha Christie (1890-1976) wrote at least 79 crime novels, with sales of more than 1 billion (I'm assuming that's total, and not just per novel..)