Archaeology has an issue with "just-in-time" research, where insufficient attention is paid to articulating a research design before fieldwork begins. Data collection, management, and analysis approaches are under-planned and, often, evolve during fieldwork. While reducing the amount of preparation time for busy researchers, these tendencies reduce the reliability of research by exacerbating the effects of cognitive biases and perverse professional incentives. They cost time later through the accrual of technical debt. Worse, these practices hinder research transparency and scalability by undermining the quality, consistency, and compatibility of data. Archaeologists would benefit from embracing the "preregistration revolution" sweeping other disciplines. By publicly committing to research design and methodology ahead of time, researchers can produce more robust research, generate useful and reusable datasets, and reduce the time spent correcting problems with data. Preregistration can accommodate the diversity of archaeological research, including quantitative and qualitative approaches, hypothesis-testing and hypothesis-generating research paradigms, and place-specific and generalizing aims. It is appropriate regardless of the technical approach to data collection and analysis. More broadly, it encourages a more considered, thoughtful approach to research design. Preregistration templates for the social sciences can be adopted for use by archaeologists.