As long as you perform regular maintenance on your smoke detectors, they will last 8 to 10 years. Smoke detectors that use lithium batteries and hard-wired units last closer to ten years. You should replace the battery backup every year and replace the entire unit every ten years. Staying on top of the replacement schedule ensures everyone in your home or business is safe at all times. Service 1st Fire Protection LLC not only installs units, but problem solves and fixes hard-wired smoke detectors that no longer function as they should.