Do Smoke Detectors expire?
I have a wired smoke detector just outside my bathroom, and when i started doing some soldering, it started going off... there was very little smoke from the flux. There is another smoke detector in the hallway, that is wired to my house alarm, and it is not nearly as sensitive. After about 30 minutes of soldering, the house alarm detector had still not made a sound.
Over budget and behind schedule...
That's how I roll :)