It's the weekend, you're out with your friends, and suddenly, you realize that you're out too late and waking up the next morning is going to be particularly awful. In the immortal words of Nike: "Just do it." Waking up at the same time is key to creating a routine that you'll be able to stick with. The silver lining? You can always take a nap later (ideally between the hours of noon and 4 P.M., when you reach the low point of your body's circadian rhythm, to reap the maximum nap-time benefits). Just make sure to keep it around 20 to 30 minutes. If it's any longer, you end up in deep sleep, meaning you may feel even worse after your nap.