In this article we explore the personal vote costs of redistricting. After redistricting, incumbents often face significant numbers of new voters—voters that were previously in a different incumbent's district. Existing conceptualizations of the incumbency advantage suggest that the cost to incumbents of having new voters should be relatively small and predictable. We propose a different formulation: a variable incumbency advantage. We argue that any incumbency advantage among the electorate is a function of short-term effects, partisanship, and electoral saliency. We use a massive untapped dataset of neighborhood-level electoral data to test our model and to demonstrate how the intersection of the personal vote, redistricting, and short-term environmental variables can provide a healthy margin to incumbents—or end their careers.