Before deciding to fight a fire, be certain that:

The fire is small and not spreading. A fire can double in size within two or three minutes. Only use a fire extinguisher when the fire is in its early stages. If the fire is already spreading quickly, evacuate and call the fire department.

You have the proper fire extinguisher for what is burning. If you don’t know what is burning, you won’t know what type of fire extinguisher to use. Even if you have an ABC extinguisher, there could be something that will explode or produce highly toxic smoke. The wrong type of extinguisher can be dangerous or life-threatening. Seven out of ten fire-related deaths occur from breathing poisonous gases produced by the fire. If there is too much smoke or if you are at risk of inhaling smoke, don’t attempt to fight the fire.

The fire won’t block your exit if you can’t control it. A good way to ensure this is to keep the exit at your back.

You know your fire extinguisher works. Inspect extinguishers one a month for dents, leaks or other signs of damage. Assure the pressure is at the recommended level. On extinguishers equipped with a gauge, the needle should be in the green zone—not too high and not too low.
You know how to use your fire extinguisher. There’s not enough time to read instructions when a fire occurs.
You have sounded the fire alarm and call the fire department, if appropriate.