For lotions, a good rule of
thumb is to use a shot glass full (about an ounce) to cover your entire
bathing-suit-clad body. Or think of it as a teaspoon per body part or area: 1
teaspoon for your face, head, and neck; 1 for each arm; 1 for each leg; 1 for
your chest and abdomen; and 1 for your back and the back of your neck.