Tracking Your Applications is important, because while Colleges will likely contact you if part of your application is missing, you never know when there will be a hard deadline that you will miss due to an incomplete application. Remember that with every interaction, you are being evaluated and that you always want to make a good impression.
Appearing to not have your act together, as demonstrated by an incomplete application, is not a good idea. Furthermore, you may have met the minimum applications requirements, but planned to add an optional piece, such as a flowing Letter of Recommendation from your Music Teacher or Coach, beyond the standard LORs. That LOR is filed by the Music Teacher or Coach directly to the Common Application, so unless you are tracking your application closely, you may not realize that they had not gotten around to filing that LOR.
A large part of stress is worry. Do I know what needs to be done? What are the deadlines? Did I get it done? Do I need to follow-up? These are the types of questions that keep us awake at night. Organizing, documenting and tracking are skills that enable busy people to fall asleep at night – they have an organized a process which determines what needs to be done when, and they document and follow that process. These are important life skills, that help you beyond this one, important process. Below is a sample spreadsheet for tracking the Application Process, by College.