The bigger the book, the longer it takes to finish writing and formatting it, the more it costs to produce and purchase, the more errors it will have, and maybe the fewer people who will buy it.
I never go to movies that are longer than two hours, because I know the movie will become a $14 nap. I am similarly reluctant to buy books with more than about 350 pages, because I doubt they will keep me interested.
In an online forum for authors, a newbie recently discussed some fine points about his debut novel -- which will have more than 800 pages.
It will be extremely difficult to persuade people to buy a huge and expensive book written by someone they've never heard of. Maybe that book should become three books, or should be drastically cut. Almost any page can sacrifice a sentence or two without suffering. Most sentences can shed a word or two, and no reader will miss them.
Publishers Weekly analyzed
stats from Amazon.com and declared that the median average word count
for books is 64,531 words, which translates to about 290 pages. While a mean average might be more useful than the median (half of the books have more words, half have fewer), the number from PW is still useful. It's probably best for new writers not to stray too far from the average.
normal for writers to love their words -- but others may not share the
love. Some writers who love their words recognize that there are just too many words. I
voluntarily cut a book I wrote from 518 pages to 432 pages, and it's
better because of the cuts. It may have been even better at 396.
I wrote for my college newspaper, I became copyeditor to prevent others
from chopping my work. I liked the control, but being in control may
have let some sub-prime work get printed.
later became an advertising copywriter, and learned that most people
glanced at an illustration and a headline, and then turned the page
without ever reading the "body copy." Only a small percentage of people
would read all of my carefully chosen words, so I modified my previous
self-protective attitude and became willing to shorten my text to
improve the appearance of the ad.
as a publisher, I frequently cut out words, lines, paragraphs, sections
and chapters to make a book look better and have an appropriate length
for its price and its market.
Like it or not, attention spans seem to be shrinking, and media bundles shrink with them. Although some editions of Tolstoy's War and Peace
have over 1,500 pages, it would probably be very tough to convince an
agent to try to sell a book that big to a publisher in 2015.
Writing to a specific length is just another discipline that professional writers have to master -- like grammar and spelling. Practice pruning!