Smoke Alarms
Smoke alarms are required on every level of the home in sleeping areas and outside bedrooms. They can also alert you to a fire in the studio or office. If you have a studio in or adjacent to your home you should definitely have alarms in and just outside the studio.
Building codes are increasingly calling for hard-wired smoke detectors with battery back-ups, wired so all alarms sound if one goes off. If you are using battery-powered detectors:

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Test your alarms frequently - the most frequent cause of failure is dead batteries.
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If your alarm begins to chirp, signaling bad batteries, replace the batteries immediately.
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Use dual-sensor detectors or some of each type
Remember that the primary purpose of a smoke alarm is to give you critical time to escape safely. Move quickly to evacuate, call the fire department, and only then consider whether it is safe to attempt to put the fire out.
FireSafety.gov has an excellent piece on selecting, installing and using smoke alarms: Smoke Alarms - Why, Which, Where.