How debt works, payoff strategies, mortgages, and when to pay down vs invest.
Avalanche (highest rate first) minimizes total interest
Avalanche pays off highest-interest debt first — mathematically optimal, hardest to stick with
Every debt has a principal, a rate, and a term
Amortization is the schedule by which a loan is paid off
APR is the annualized rate without compounding
Fixed-rate mortgages protect you from rate increases; ARMs cost less initially but carry risk
Federal and private student loans have very different rules
Compare debt rate to expected after-tax investment return