Life Cycle Assessments (LCAs) are essential for evaluating the environmental impact of buildings but often rely on incomplete or unverifiable data. Even more troublesome is the typical LCA assumption of cradle-to-grave design, which runs counter to urgent calls for building and material reuse and precludes alternative timelines of “life” in the life cycles assessed. Through a small-scale case study—a structure made from reused components, designed for zero operational emissions, and intended to weather and decay in collaboration with other species— the authors highlight the challenges of assessing structures composed of salvaged materials through conventional LCA methods. Thus, this paper proposes rethinking LCA methodologies, particularly the “reuse factor” and its assumptions about the useful lifetimes of buildings and their constituent parts.