   ere are four main components to habit formation: the context cue, craving, behavioral repetition, and the reward. The context cue can be a prior action, time of day, location, or anything that triggers the habitual behavior. This could be anything that one associates with that habit, and upon which one will automatically let a habitual behavior begin. The cue leads to a craving or desire. The craving is the motivational force behind the habit. You don’t crave the habit itself; you crave the outcome you believe it will bring. The behavior is the actual habit that one exhibits, and the reward, such as a positive feeling, reinforces the "habit loop". A habit may initially be triggered by a goal, but over time that goal becomes less necessary and the habit becomes more automatic. Intermittent or uncertain rewards have been found to be particularly effective in promoting habit learning. A variety of digital tools, such as online or mobile apps, support habit formation. For example, Habitica uses gamification, implementing strategies found in video games to real-life tasks by adding rewards such as experience and gold. However, a review of such tools suggests most are poorly designed with respect to theory and fail to support the development of automaticity. Shopping habits are particularly vulnerable to change at "major life moments" like graduation, marriage, the birth of the first child, moving to a new home, and divorce. Some stores use purchase data to try to detect these events and take advantage of the marketing opportunity. Some habits are known as "keystone habits," and these influence the formation of other habits. For example, identifying as the type of person who takes care of their body and is in the habit of exercising regularly, can also influence eating better and using credit cards less. In business, safety can be a keystone habit that influences other habits that result in greater productivity. A recent study by Adriaanse et al. found that habits mediate the relationship between self-control and unhealthy snack consumption. The results of the study empirically demonstrate that high self-control may influence the formation of habits and in turn affect behav  |