FWIW, a ten-year replacement cycle is typically indicated for ionization-type smoke/CO detectors, and not photoelectric units. And even for the ionization type detectors, the "10-year" stipulation is somewhat arbitrary, as elaborated on in the post linked below.
FWIW, even if @jtp10181's smoke detectors were the ionization-type, about 95-96% of the Americium-241 would not have decayed after ~30 years.
