Sleep is a natural part of our lives. It’s a subject that many of us instinctively assume we know a lot about. But sleep is surrounded by many myths and misinformation.

Sleep specialists Lawrence Epstein, M.D., and Stephanie Silberman, Ph.D, dispel some of the more common myths about slumber.

1. Myth: The optimal amount of sleep is eight hours.

Fact: We often hear in the media that eight hours is the magic number for sufficient sleep. But following the eight-hour myth can lead you to “strive for something that’s not necessary for [you] or attainable,” says Silberman, who’s also author of The Insomnia Workbook: A Comprehensive Guide to Getting the Sleep You Need.

In fact, “Everybody is so individual.” One person may need five hours of sleep while another functions best on nine hours, she says.

How do you know your magic number? “It depends on how you feel during the day,” she says. Another way to tell is when you’re on vacation, says Dr. Epstein, who’s also the chief medical officer of Sleep HealthCenters and an instructor in medicine at Harvard University.

“Let yourself sleep as long as you need.” At first, you’ll probably sleep a lot because it’s likely you’re sleep-deprived, he says. However, at the end of the week, you’ll probably be falling asleep and waking up at the same time.

Figuring out how many hours you need to sleep isn’t the hard part; it’s actually continuing to sleep this many hours, he says.

2. Myth: Watching TV helps you fall asleep.

Fact: TV is stimulating and can interfere with falling asleep, Silberman says. But there are many people who can watch TV and have no issues, she says.

The takeaway? “If you already have sleep problems, you don’t want to do anything that’s stimulating in bed.” That includes watching TV, using the computer and texting on your phone.

3. Myth: A nap during the day has no effect on nighttime sleeping.

Fact: According to Silberman, “We only need a certain amount of sleep across a 24-hour period. If you take an hour-long nap, you need an hour less of sleep.”

Also, people who have trouble sleeping at night should avoid daytime napping, Dr. Epstein says.

4. Myth: Alcohol helps you sleep.

Fact: Alcohol can help you fall asleep quicker, but it causes disrupted sleep, according to both experts. Dr. Epstein says that sleep is lighter, and you’re more restless.

5. Myth: Insomnia only happens to people who’re depressed or anxious.

Fact: Insomnia can happen to anyone, Silberman says. A variety of factors can contribute to insomnia, including medication, disorders such as restless leg syndrome and even your own behaviors. She says that transient insomnia, which lasts less than a month, is very common.

6. Myth: If you can’t fall asleep, stay in bed longer.

Fact: Some people assume that if they spend more time in bed, they’ll increase the number of hours they sleep. But Silberman says that this “rationale completely works against” individuals.

The more time spent while awake in bed actually boosts the negative association between bed and sleep. Instead, she suggests spending less time in bed to improve your sleep.

7. Myth: Sleep disorders are difficult to treat.

Fact: Sleep disorders are highly treatable, and medication isn’t a must. While it can depend on the severity of the sleep disorder, Silberman says that insomnia, for instance, can be treated in four or five sessions with cognitive-behavioral therapy (CBT). (This number of sessions even works for people who’ve suffered with insomnia for a long time, she says.)

8. Myth: You need less sleep as you get older.

Fact: Actually, an adult needs the same amount of sleep throughout his or her lifetime. What changes, Dr. Epstein says, isn’t the amount of sleep you need, it’s how well you’re able to sleep.

Simply, “it becomes harder to get the same amount of sleep.” Sleep becomes more fragmented, and people sleep lighter and awaken more often, he says.

9. Myth: You can train yourself to get by on less sleep.

Fact: There’s no way to manipulate your sleep, Dr. Epstein says. In fact, “your sleep debt will [only] build up and affect your performance.” Studies have shown that the more sleep-deprived people are, the worse they perform on cognitive and reaction time tests, he says.

Research has also revealed that “people’s perception of their own sleepiness plateaus,” so they don’t even realize just how sleepy they truly are. This, of course, has serious implications when people are supposed to function fully, such as when they’re driving or working.

10. Myth: Falling asleep during the daytime means you’re lazy.

Fact: Falling asleep during the day “isn’t a personality defect,” but instead means you’re sleep-deprived and “haven’t been getting enough sleep at night,” Dr. Epstein says.

Because this is a sign that you haven’t been meeting your sleep needs, he adds, it’s important to consider what you can do to get back to sleeping well.