This paper gives an overview of subrecursive hierarchy theory as it relates to computational complexity and applies some of the concepts to questions about the size of programs in subrecursive programming languages. The purpose is three-fold, to reveal in simple terms the workings of subrecursive hierarchies, to indicate new results in the area, and to point out ways that the fundamental ideas in hierarchy theory can lead to interesting questions about programming languages. A specific application yields new information about Blum's results on the size of programs and about the relationship between size and efficiency.