Money & Why fictional learning case. This is an editorial scenario, not a real member’s story or a personal recommendation. Any KRW figures are illustrative Korean won amounts, not currency conversions. Eligibility, taxes and account rules must be checked in the relevant country.
A single-income family of four has two children and about KRW 280 million remaining on the mortgage. The household depends heavily on one person’s earnings.
Holding too much cash can slow long-term investing, but holding too little can make a job loss or illness especially difficult when both living expenses and mortgage payments continue.
How many months of essential spending would you keep, and how would job stability, insurance coverage, and the other spouse’s ability to return to work affect the number?
Work through this case
1
Use essential spending plus required debt payments as the basis for reserve months, rather than the mortgage balance itself.
2
List possible job-search time, confirmed support payment dates and extra costs. Keep uncertain assistance out of the base budget.
3
Test a short and a longer income gap and locate the first cash shortfall. There is no universal number of reserve months for every one-income family.
Discussion exercise: Compare two workable options and identify the missing fact that could change your choice. Keep personal amounts approximate and never share account or identity information.
Editorial clarification and worksheet added September 19, 2026.