Task and activity tracking has been an effective industrial management and research technique for generations. It is applied to workflow optimization, group coordination, task sequencing, individual time management and environmental exposures. Appropriately, task tracking technologies are migrating to personal mobile devices. At the same time, individual survey approaches have been advanced tremendously as mobile apps. We report on a method of dynamic task registration with momentary assessment systems in natural environments that apply knowledge of context. We describe how the app was refined by a user acceptance study and its deployment in studies on agricultural exposure and industrial operations.