A previous residential mobility model (Speare, 1974) assumes an additive relationship between residential satisfaction, desire to move, and mobility. This paper elaborates the model and applies it to intercounty migration. An interaction between community satisfaction and expectations to migrate is hypothesized which distinguishes four groups of decision makers. A survey in Durham, North Carolina and a unique mobility followup over eight years provide the data to test the model and the interaction. Furthermore, using various time periods for identifying migrants offers some methodological insights. Results support Speare’s general formulation but only after the interaction is taken into account. A three-year migration interval is found to be appropriate.