Smoke detectors are one of the simplest, most powerful tools for saving lives in a fire emergency. Yet, many homeowners and landlords unknowingly make mistakes that reduce their effectiveness. A poorly placed, outdated, or neglected smoke alarm can fail when it matters most. In this expert guide, we break down the most common smoke detector mistakes, explain why they happen, and show you exactly how to fix them. If your goal is a safer, smarter home, this is your essential checklist.