The answer to 'how long does carbon monoxide detector last' is that most carbon monoxide detectors have a lifespan of 5-7 years. These devices contain sensors that gradually degrade over time, so they need to be replaced periodically to ensure they continue working properly.
Carbon monoxide detectors should be tested monthly and replaced according to the manufacturer's recommendations, usually every 5-7 years. Some higher-end models may last up to 10 years, but it's important to follow the guidelines provided by the manufacturer for your specific device.