Many factors work to destroy the naturally white smile we are born with. Tobacco, certain foods we eat, and certain drinks actually stain teeth. These substances continually work on our teeth causing our white smile to gradually fade.
Hot coffee and tea are especially hazardous to your smile because they change the temperature of your teeth. This temperature change (hot and cold cycling) causes the teeth to expand and contract allowing stains to penetrate the teeth. Just cutting down on coffee and tea alone can go a long way to creating a great smile.
Foods that are slightly acidic are also dangerous to your white smile. These foods open up the pores of the tooth enamel allowing stains to more easily move into the tooth.