Traditional wills doctrine was notorious for its formalism. Courts insisted that testators strictly comply with the Wills Act and refused to consider extrinsic evidence to construe instruments. Yet the 1990 Uniform Probate Code revisions and the Restatement (Third) of Property: Wills and Donative Transfers replaced these venerable bright-line rules with fact-sensitive standards in an effort to foster individualized justice. Although some judges, scholars, and lawmakers welcomed this seismic shift, others objected that inflexible principles provide clarity and deter litigation. But with little hard evidence about the operation of probate court, the frequency of disputes, and decedents’ preferences, these factions have battled to a stalemate. This Article casts fresh light on this debate by reporting the results of a study of every probate matter stemming from deaths during the course of a year in a major California county. This original dataset of 571 estates reveals how wills law plays out on the ground. The Article uses these insights to analyze the issues that divide the formalists and the functionalists, such as the requirement that wills be witnessed, holographic wills, the harmless error rule, the ademption by extinction doctrine, and the antilapse doctrine.