8 changes to make in your 30s that will set you up for lifelong success

1. Stop smoking. If you've started smoking, stop immediately, while you can't undo the damage you may have already incurred from smoking, research suggests that those who quit before age 40 have a 90% lower mortality risk than those who continue. 2. Start going to sleep and waking up at the same time every day. If you oversleep for even a few days, experts say you risk resetting your body clock to a different cycle, so you'll start getting tired later in the day. Avoid a lifetime of sleep issues by sticking to bedtime and wakeup routines whenever you can. 3. Start exercising regularly. In the later half of your 30s, you start losing muscle mass, so it's especially important to exercise at this time. But remember to choose physical activities you really love, since you're less likely to continue exercising if you dislike your workouts. 4. Start keeping a journal. Even if you'd prefer to keep your musings to yourself, putting your thoughts and feelings on paper can help you deal with stressful events.