Generally, writers need to follow the rules. Thanks to rules, writers write clearly, editors edit consistently, and readers read with comprehension.

Some rules are, of course, strict and non-breakable. But others are breakable, and violating them permits us to write with clarity and power. Here are three rules to break under the right circumstances.

Breakable rule 1: Don’t start sentences with but, and, or other conjunctions

Break this rule when doing so shortens sentences and adds impact. For example:

“The terrorist attacks of Sept. 11, 2001 took thousands of lives and still affect our country today.”

That’s fine as written, but stronger this way:

“The terrorist attacks of Sept. 11, 2001 took thousands of lives. And they still affect our country today.”

The rules also say the conjunction because shouldn’t start a sentence. But again, starting a sentence with because may emphasize a point. We could write:

“The Senate failed to pass the bill because too many senators thought it would increase taxes.”

That’s fine if we’re emphasizing that the bill failed. But we may want to emphasize why the bill failed:

“Because too many senators thought the bill would increase taxes, the Senate failed to pass it.”

So feel free to start sentences with conjunctions if doing so emphasizes a point or increases clarity.

Breakable rule 2: Don’t use incomplete sentences

Many writers still have their fourth-grade teacher sitting on their shoulders. And those teachers take off points for writing incomplete sentences. It’s time to let the teacher go into semi-retirement, because sentence fragments may strengthen writing and add impact.

We could write this about events that took place in 2017:

“A series of disasters hit the United States from August through November. Four hurricanes pounded the country, followed by the mass shooting in Las Vegas, deadly wildfires in California, and the church shooting in Texas.”

There’s nothing wrong with those sentences. They violate no rules and are fine as written. But using incomplete sentences strengthens our point:

“A series of disasters hit the United States from August through November. Four hurricanes. The mass shooting in Las Vegas. The deadly wildfires in California. The church shooting in Texas.”

As always, your goal is clarity.

Breakable rule 3: Don’t end a sentence with a preposition

This is another rule from elementary school days. But sometimes breaking this rule improves clarity. Here’s an example:

“Everyone cancelled,” Bill said. “Now I have no one with whom to golf.”

Sounds silly, right? No one talks like that. So write:

“Everyone cancelled,” Bill said. “Now I have no one to golf with.”

One caveat—don’t end a sentence with an unnecessary preposition, such as in this sentence:

“I don’t know where my phone is at,” Jeff said. “I’ve never lost it before.”

There’s no need for the prepositions at or before. At adds nothing and before is redundant, because it’s obvious Jeff can’t be speaking of the future.

As long as the preposition is necessary, however, ending a sentence with one is not a writing practice to be afraid of.

The two keys in deciding when to break the rules are, 1) What tone are you trying to convey? If you want a more informal tone, violating one of these rules may be fine. 2) What are the expectations of the publication, if any, you’re writing for? Ultimately you must follow their rules.