Understanding service life requirements of ‘engine air cleaners’ (EAC) and ‘air induction filters’ (AIF) in real world conditions is important for robust designs. The performances of EAC and AIF are generally measured and evaluated in the lab using standard test procedures which may or may not represent real world conditions. This paper compares some design specifications for light, medium and heavy duty EAC. Various field evaluations are presented to better understand how EAC and AIF perform in real world conditions. Service life expectations are also discussed based on field evaluations. Service life of an EAC is related to its dust/contaminant holding capacity and its restriction rise over time. Evaluating performances of EAC in real world conditions provide meaningful data. Analysis in this paper has been presented mainly for light and medium duty vehicles (passenger cars & light trucks). Heavy duty engine filtration systems are briefly compared and discussed as well.Initial efficiency is one of the key performance measures of automotive AIF. Typical lab performance levels of initial efficiency and dust capacity for three [1, 2, 5] major air filtration technologies are presented.