The answer to 'which is better smoke detector or' is that smoke detectors are generally better for home fire safety than carbon monoxide (CO) detectors. Smoke detectors are designed to detect the presence of smoke, which is one of the first signs of a fire. They can alert you to a fire early, giving you and your family more time to evacuate safely.
Smoke detectors are also more affordable, easier to install, and have a longer lifespan than CO detectors. Most building codes require smoke detectors in homes, while CO detectors are only mandated in some areas. That said, it's recommended to have both smoke and CO detectors installed throughout your home for comprehensive safety.