finance.tooljo.com — blogPlain-English notes on mortgages, FIRE math, and personal-finance edge cases.https://finance.tooljo.com/en-usWhy an extra $200/month in year 1 saves more than $200/month in year 25https://finance.tooljo.com/blog/why-extra-principal-matters-most-early/https://finance.tooljo.com/blog/why-extra-principal-matters-most-early/Counterintuitive math: the same extra-principal payment is worth roughly 6× more in your first year than in your last. Working through why, with numbers.Tue, 28 Apr 2026 00:00:00 GMT