Although the methodology for developing life predictions has been in use for some years in the industry, it is becoming clear that the implied precision in the use of a single value in years cannot be scientifically supported due to much variability between the measurement of an assumed exposure and the actual exposure and observation conditions. All print life predictions assume that the print is exposed to only one condition for its complete life. That is, a light fade prediction assumes no ozone exposure (or exposure to any other industrial gases), and no effects from high or low humidity. Obviously such assumptions are likely to be invalid in almost all real life exposure situations and the data for the long term effects of combined exposures is scant to say the least. This paper examines the implications of this on real life print exposure.