As virtual reality and mixed reality systems reach broader adoption, more companies require the need for positional tracking to precisely match user movement with rendered content. Yet what initially began as a key competitive advantage has quickly evolved into a complex yet commonplace commodity. Lighthouse has been open-sourced. Inside-out positional tracking can be done with consumer-grade sensors. And future mobile devices will likely come with much of the sensor package required to enable 6-DoF positional tracking. While some aspects of positional tracking are being commoditized, others are still difficult open challenges. We'll explore the differences between visual odometry and full SLAM, sparse point clouds and dense models, and costs associated with different kinds of systems.