The human brain is not built for multi-tasking, and this applies to habit formation as well. Each new behavior you attempt to track adds to your total managerial load. This is the mental energy required to remember, perform, and record a task. When you track too many variables, you experience a fragmentation of focus. This results in a high failure rate across all tracked metrics.
Essentialism in habit tracking is the practice of identifying keystone behaviors. These are specific habits that create a ripple effect. For example, consistent strength training often improves sleep quality and nutritional choices automatically. When you focus on a keystone habit, you gain the benefits of multiple behaviors while only paying the cognitive tax for one.
To determine which habits are worth tracking, you must analyze the return on investment for each. A high-leverage habit is one that makes other tasks easier or unnecessary. If you track ten habits but feel overwhelmed, you are likely tracking low-value behaviors (such as 'drinking eight glasses of water') at the expense of high-value ones (such as 'four hours of deep work').
The rule of three is a useful heuristic. Attempting to install more than three new habits simultaneously is statistically likely to result in zero long-term retention. Focus on a maximum of three until they reach the point of automaticity. This usually takes between 18 and 254 days, depending on the complexity of the task.
Tracking should be a temporary scaffolding, not a permanent job. Once a behavior is truly automatic, you should stop tracking it. The goal is to spend your life living your routines, not managing the data of your routines. Simplify your system to the point where it supports your life without becoming a distraction in itself.