The Short Version
When writing a story, use parentheses as sparingly as possible.
The Long Version
There are some forms of punctuation that are generally frowned upon in professional writing, such as the interrobang (?!), repeated exclamation marks, and emoticons. Using parentheses to create parenthetical statements, on the other hand, is perfectly acceptable punctuation usage. So why do I recommend that you do so sparingly?
One of the greatest challenges of writing is getting your thoughts to flow smoothly from one to the next without any hard-to-follow leaps that will be difficult for readers to follow. You want your story to flow naturally and logically, A to B to C to D and so on rather than G to W to T to G again. If this is done well, readers can breeze through hundreds of pages at a time without ever having to pause and figure out what is being said—your thoughts will flow as naturally through their minds as their own thoughts do.
Now, if you read this post, you know that parentheses are specifically supposed to be used to insert information into a sentence or paragraph that is no more than loosely related to the topic at hand—“flavor” text that might be interesting, might be funny, but isn’t actually needed. In other words, parentheses are intended to insert information that will specifically interrupt the smooth, logical progression of thoughts that most writing is intended to achieve. It is hard enough to manage such smooth prose normally; but if you’re adding extraneous thoughts left and right, it’s going to be even more difficult. So use parentheses as sparingly as possible.
What qualifies as “sparingly” will vary depending on the style of story you’re writing. If your story is being narrated—either in first-person by one of the characters or by an omnipotent third-person narrator with its own personality—then you’ll be able to use more parenthetical statements than in other situations. In these situations, parenthetical statements can be used to mimic the often-erratic nature of speech and oral storytelling, to give your protagonist or narrator more of a realistic and engaging personality.
Third-person-limited and narrator-less third-person-omniscient stories, however, aren’t narrated by characters. In those sorts of stories, parenthetical statements will be more likely to interrupt the flow of the narrative—I would go so far as to recommend avoiding parentheses entirely in such stories, if at all possible.
|Found this nice little explanation here.|