So, the 10 year working life of an American smoke detector is bested by the 2,500 year working life of a Soviet smoke detector.
What a glowing recommendation!
heh.
Thing is, the plutonium they put in has a half life of 12 years, while the americium is 432. Starting with Pu would therefore only get you another year or so, but be complicated by drastically higher emissions the first few years.
The 10 year lifespan is more due to:
1. Nobody wanting to clean their smoke detectors.
2. The risk of other components failing.
At $10-40 per, it's not worth the labor, but you could theoretically have an adjustable smoke detector where, every decade or so, you move it up a sensitivity notch.