Fires occur frequently in the United States, with a fire department responding every 15 seconds on average. Most fires occur in homes, and residential fire deaths usually happen at night when people are sleeping. Common fire causes include wiring issues, equipment problems, and combustible materials. Different types of fires are classified based on the materials burning. Fire extinguishers are labeled for the classes of fires they can effectively put out, and must be properly maintained. Smoke alarms should be tested monthly and replaced every 7-10 years to help detect fires early. Fires can grow and conditions can become dangerous or unsurvivable very rapidly, emphasizing the importance of prevention and having an escape plan.