Determination of atomic and molecular lifetimes by delayed coincidence photon counting with photomultipliers two or more years old may lead to erroneous results caused by afterpulses and even direct photodecay in perfused helium. Spurious lifetimes as low as 15 nsec for theB2&Sgr;u+(v′=0)state ofN2+and the C3&Pgr;g(v′ = 0) state of N2have been observed.