We all know subplots are basically a device to give your story a word count that will make it a book-worthy document, right? Wrong. Subplots weren't created to fatten up stories to please consumers. At least, they shouldn't be.
Here is what subplots can really do for your book:
Subplots allow you to add depth to your characters. Your plot may revolve around a murder mystery, but a subplot involving a troubled marriage or a struggle with alcoholism gives you the opportunity to dive deeper into a character's life. Your characters have a place in your plot and can even drive the plot. Giving them subplots gives them their own place in the story.
Subplots can serve as a thread to tie books in a series together. A subplot that snakes through the background of one book can grow into the main plot for the next book. It gives your story layers that can shift from book to book.
Subplots give your story a reality that would otherwise be vacant. Real life is messy. Books are a series of carefully constructed events. Subplots give the illusion of chaos. They make things seem real-world crazy and messy.
I'm not suggesting that you shouldn't use subplots to beef up your book. I am, however, suggesting you don't consider upping your word count as beefing up your book. Readers will see it for what it is: padding. Subplots should be used to give your characters and story depth. That is how you beef up your book.
Richard Ridley is an award-winning author and paid CreateSpace contributor.