also, keep your gift receipts. some stores won't let you return a gift without one. others may give you a store credit. check return policies in-store and online. many retailers extend their deadlines until late january, during the holidays. that works in your favor. make sure you have i.d. some stores use computerized return systems to detect abuse. u.p.s. has named january 2nd as the biggest return day of the year. you may want to wait until next weekend to head to the mall. if you ate too much on christmas, here's advice to get back on track for the new year. abstaining from food for 16 to 18 hours could be key to living longer. a review of past studies in "the new england journal of medicine" suggests that intermittent fasting, when you limit your eating to six to eight hours a