In this article, we discuss two negative polarity item (NPI) adverbials: in years (and its cousins in days, in months, etc.) and until. We argue that much is to be gained by analyzing the two in juxtaposition. We first explore in years, following our approach in Iatridou and Zeijlstra 2017; on the basis of our analysis of this item, we then explore until. Our approach permits a unified account of until, whose behavior has led researchers to consider it lexically ambiguous. The commonalities between in years and our unified until also allow us to explain why both these boundary adverbials are strong as opposed to weak NPIs.