The best advice I've heard is if you can get better interest rates with savings/investments then put your money there, if the interest on your debts are higher

The best advice I've heard is if you can get better interest rates with savings/investments then put your money there, if the interest on your debts are higher then pay them off with your spare money. When paying off your debts you want to pay off the debt with the highest interest rate first (after you've met all your minimum payments of course). Things to be wary of with paying off your mortgage is that some times there are penalty clauses in your contract so if you pay off too much you have to pay an additional fee (more common for the fixed period of fixed rate mortgages, but always check before overpaying your mortgage).