(Sunk costs) A young couple has made a nonrefundable deposit of the first month's rent (equal to $1,000) on a 6-month apartment lease. The next day they find a different apartment that they like just as well, but its monthly rent is only $900. They plan to be in the apartment only 6 months. Should they switch to the new apartment? What if they plan to stay 1 year? Assume an interest rate of 12%.