Even people who do have that diligence can be caught out. You do the calculation, make the purchase and a week later encounter an unexpected expense like your c

Even people who do have that diligence can be caught out. You do the calculation, make the purchase and a week later encounter an unexpected expense like your car breaking down, or you lose your job. You may now find yourself unable to make the full repayment despite having thought about the purchase before making it.