This chapter offers a reconstruction of the development of preaspiration in the Sámi languages. Like the Celtic languages, this family shows extensive microvariation in synchronic patterns of preaspiration. I argue that the clear demarcation between phonetic-phonological and phonological rules offered by the life-cycle model provides new insights into both synchronic patterns and diachronic developments known from the literature. Preaspiration in the Sámi languages exhibits particularly intricate interactions with phonological quantity; the chapter shows how they can be understood in terms of both phonetic and phonological rules in different languages. It is argued that the Sámi languages are particularly valuable in the context of the proposed theoretical framework due to the intricate interplay of phonetic and phonological patterns that shed new light in particular on the processes of rule scattering and rule generalization.