Previous research has shown that money management contributes to over-indebtedness. This article sheds new light on this relation by looking at factual money management and its mental underpinnings, mental accounting. In a conceptual model we propose that fuzzy factual and mental money management practices aggravated by lack of congruency between factual and mental structures play an important role in over-indebtedness. Twenty-five in-depth interviews deliver preliminary support for this proposition. Successful financial control seems to build on efficient and inter-coordinated factual and mental money management. This reduces the willpower necessary for controlling financial behavior and helps to prevent and fight over-indebtedness.