In the high temperature oxidation of metallic alloys oxide scale strains and in particular critical scale strains play a key role with regard to scale adherence. Scale spallation/exfoliation is a vital issue for not only long term alloy performance but also steel sheet production. In many cases materials selection is based on thermodynamic considerations and short term laboratory data, not taking into account changes in the oxidation mechanisms resulting from stresses induced by thermal cycles, oxide growth, specimen or component geometry, or other operational factors. This paper presents a very concise summary of the present knowledge in the form of an approach to a comprehensive scale failure model which is based on a number of microscopic and macroscopic system parameters. This failure model is part of an on-going work which aims at a computer-assisted assessment of oxide scale mechanical reliability.