This paper briefly reviews methods to predict the useful service life of high temperature alloys exposed to thermal cycling conditions. Particular attention is given to chromia-scale forming alloys and the shortcomings are addressed of applying existing (and successful) models developed for alumina-scale forming alloys to chromia formers. The chromia-forming 800HT alloy is used to provide an example of the tractability of cyclic oxidation lifetime prediction. The oxidative effects of elements that are common minor and major additions to commercial, chromia-forming alloys are also discussed. The principal minor elements of concern are Si, Ti, Al, Mn, and reactive elements such as Ce, La, and Zr. It will be shown that variation of minor-element contents within the specified range of a given alloy can result in markedly different cyclic-oxidation behaviors. In most cases the oxidative effects of minor elements must be analyzed collectively rather than independently. An important consequence of this is that accurate modeling of oxidation performance must ultimately require an understanding of this apparent interdependence between the alloying elements.