The number the monthly payment hides
Loans are sold on the monthly payment, because a manageable monthly number makes almost any purchase feel affordable. But the figure that actually matters is the total interest — what the loan costs you on top of what you borrowed. On a 30-year mortgage, that can approach the size of the loan itself.
The lever most people don't use is the term. Shortening it raises the monthly payment but slashes total interest, because the balance is outstanding for fewer years. Extra payments do the same thing — every dollar above the minimum goes straight to principal and compounds in your favour for the rest of the loan.
