This Article explores how “habit evidence†will become a catalyst for a new form of digital proof based on the explosive growth of smart homes, smart cars, smart devices, and the Internet of Things. Habit evidence is the rule that certain sorts of semiautomatic, regularized responses to particular stimuli are trustworthy and thus admissible under the Federal Rules of Evidence (“FREâ€) 406 “Habit; Routine Practice†and state equivalents. While well established since the common law, “habit†has made only an inconsistent appearance in reported cases and has been underutilized in trial practice. But intriguingly, once applied to the world of digital trails and the Internet of Things, this long dormant rule could transform our “quantified lives†into a significant new evidentiary power. In fact, habit evidence as quantified fact may become weaponized to reimagine trial practice in the digital age.