Protect Your DNA As you age, the ends of your chromosomes become shorter. This makes you more likely to get sick. But lifestyle changes can boost an enzyme that makes them longer. Plus, studies show diet and exercise can help protect them. The bottom line: Healthy habits may slow aging at the cellular level. Play to Win An 80-year study found people who are conscientious — meaning they pay attention to detail, think things through, and try to do what’s right — live longer. They do more for their health and make choices that lead to stronger relationships and better careers. Make Friends Here’s another reason to be grateful for your friends: They might help you live longer. Dozens of studies show a clear link between strong social ties and a longer life. So make the time to keep in touch. Quit Smoking We know giving up cigarettes can lengthen your life, but by how much may surprise you. A 50-year British study shows that quitting at age 30 could give you an entire decade