It's easy to let sin get out of control in your life. Sometimes you don't even realize that there are areas of sin in your life because the enemy blinds you and gives you excuses for certain things. This study is really helpful for practicing the spiritual discipline of self-examination, which can open up your eyes to sins lingering in your life. I like to do this during the week of the Feast of Unleavened Bread -- removing the leaven of sin from my life periodically each year.
Repentance should, of course, be a regular thing. But a study like this is good to do on a regular basis at least once a year (or more). Because it helps you to dive deeper into your heart and examine all of the nooks and crannies where sin might be lingering. Doing this helps you to draw closer to God and have a more effective prayer life.
I love the study. It's in depth, thorough, and challenging! I really want to do this one at least once a year every year!!