As many excellent writers will tell you, grammar matters.
But sometimes there’s an exception. A free ride. A hall pass.
Under some very specific circumstances… you can BREAK THE LAW!
For Dramatic Effect
Sometimes you want to emphasize how much something really, really sucks. Or really, really rocks. Or really, really is not true.
Like: It ain’t easy.
Yes, you may break the laws of grammar to make your point. As long as you know the laws of grammar, that is, and know you’re breaking them.
Stay True to Your Character
Let’s say your character is a ten year old who answers the phone.
It’s grammatically correct to say, “To whom am I speaking?” But would your character know that?
It’s okay to break the laws of grammar if your character wouldn’t know those rules.
Here’s an important caveat: Let’s say you’re writing the entire novel from the perspective of a grammatically-challenged character.
It’s been done before – Mark Danielewski’s House of Leaves uses “should of” and “could of” to great effect – but you should know you’re signing up for a serious challenge.
When Rules are in Flux
Sometimes there’s just no good answer. For example, making a name that ends in -s possessive.
That’s Mr. Jones’ cat? That’s Mr. Jones’s cat?
When even the pros can’t decide – you get to do what you want! Isn’t that liberating?
Now get writing!