Three main refi types: Rate/term (lower rate, keep or change term), Cash-out (borrow against accumulated equity), and Streamline (simplified refi on existing FHA or VA loans).
Break-even math: (total closing costs) / (monthly payment reduction) = months to recoup. Under 24 months = no-brainer in most cases. 24–48 months = depends on how long you'll keep the loan. Over 48 months = rarely worth it.
California cash-out refi is capped at 80% LTV on most programs. Investment-property cash-out typically caps at 75%. Seasoning requirements (how long you must own before refinancing) vary by program.