I have an ADT security system and the main smoke detector is connected to the alarm system. If we are not home or if we don't hear the alarm going off for some reason (like when my husband left bacon cooking and came out into the garden!) it calls the fire department.

I feel good about this because it would protect my dogs if nobody was home.

My other smoke detectors have lithium batteries that are supposed to last for 10 years. You are still supposed to test them from time to time. I bought two for my son as well.