Here is a little list of the word count of some well known pieces of fiction. For some reason, despite how subjective literature is, word count comes into play with strict regulations. Of course, word count doesn't translate to quality. Thus, for comparison's sake, below are a few books with their word count, found using AR BookFinder. A star (*) after the author's name indicates the word count came from another source and may be a less trustable estimation. Take these numbers as estimations with a +/- 1,000 word range.
Old Man and the Sea - 26,560 - Ernest Hemingway
Animal Farm - 29,060 - George Orwell
Of Mice and Men - 29,572 - John Steinbeck
Hamlet - 32,044 - William Shakespeare
Heart of Darkness - 38,206 - Joseph Conrad*
Fahrenheit 451 - 45,910 - Ray Bradbury
The Great Gatsby - 47,094 - F. Scott Fitzgerald
Slaughterhouse Five - 49,459 - Kurt Vonnegut
When I finish a sentence, I add one space, then move on. And yet I find many classmates (i.e. under thirty) adding two spaces after a period. Why do they do this, and is it at all something worth doing? (The short answer is no, but let me explain.)
Typewriters. Not the 1980s typewriters that were half computers, half type machines. The double space habit comes from old manual typewriters, which employed monospace fonts. In comparison, fonts used nowadays like Helvetica and Times New Roman are proportionally spaced. This means that the letter i gets less space than the letter m. In monospace, both get the same amount of spacing (due to the moving mechanics of an old typewriter). As such, there would be a little space around an i to compensate for the larger m. Thus, double spacing after periods was used to make the end of a sentence more obvious. Of course, that was over thirty years ago. Today we only use monospace fonts if we want to create the good ol' feeling of typewriters, which most people of my generation have never even touched. So why do people still do this? Either they want to act older than their age, or they never got the memo that double spacing is wholly unnecessary. And, in practice, for every person who double spaces consistently after a period, there are at least two who, somewhere in their twelve page paper, forget to double space once. Just once. And that is inconsistent and ugly.