Final answer:
Smoke detectors in one- and two-family dwellings must be replaced every 10 years to ensure their effectiveness.
Step-by-step explanation:
According to NFPA 72, smoke detectors in one- and two-family dwellings must be replaced every 10 years. This guideline ensures that the smoke detectors continue to function properly and provide reliable fire detection.
Over time, the components in smoke detectors can deteriorate, including the radioactive element americium and the battery. Therefore, it is important to replace smoke detectors regularly to ensure their effectiveness.