How can we use smart reminder systems to help people accomplish long-term personal goals, such as building habits? This project uses the idea of "microreminders", or reminders of very short actions users can complete to make progress towards their habit, sent at a moment when the action is both useful and easy to accomplish. Our app, named Dory, combines native iOS contextual sensing and iBeacon technology to detect ideal moments in which to present users with reminders of actions that help them build habits over time. Results from a month-long deployment of Dory showed that microreminders help reduce the cost of taking action towards a goal, and that this effect is reinforced over time. A paper describing this study is currently under submission for CHI 2018.