With the advent of ubiquitous computing, precision health, defined as the practice of personalized health, promises a future where we can prevent disease and maximize wellbeing. To succeed, we must engage healthy individuals to comply with continuous monitoring and behavior change. In this talk, I focus on the challenge of engineering precision health approaches in mundane environments by leveraging concepts from affective and embedded computing, behavioral economics, and human-centered design. I will discuss in depth flagship projects on stress management: a) repurposing existing devices into “sensorless” stress sensors, and b) minimal transformation of car and office furniture to regulate breathing. I will close with a vision of the future of precision health engineering where affordable design and machine learning can drive long-term behavior change. I will quickly describe some forward-looking exploratory projects to help improve people’s health by recommending personalized interventions that are very easy to use, that defeat novelty effects, and that can even operate at a subconscious level.