JV Jones and YourPalSal review the differences between systems and goals. DIscussing important characteristics of each, and how having a system can set you up for success regardless of the goal being reached. As for how this applies to being "debt free", breaking your system to bite sized achievable pieces which wont result in burnout is key.
A few external references
Scott Adams: Goals vs System https://www.scottadamssays.com/2013/11/18/goals-vs-systems/
Lifehacker: Get More Done By Focusing on Systems Instead of Goals https://lifehacker.com/get-more-done-by-focusing-on-systems-instead-of-goals-1786245764