Sleep/Legends

"Have you ever thought about sleeping, boss?''" "Which is, exactly, what?" "''Sort of like being shot until you're unconscious, except there's no bacta, and you often end up feeling better than when you started."

- Wes Janson and Wedge Antilles

Sleep was a state of unconscious rest needed by a wide variety of species across the Galaxy, including Humans, Hutts, Gamorreans, Bothans, and Kaleesh. Interestingly, Gand required a fraction of the sleep Humans did, an ability that helped save Ooryl Qrygg's life on Talasea. The Bith race of Clak'dor VII also did not sleep. Instead, they would enter a trance, during which they were almost as aware of their surrounding as awake while receiving the same amount of rest as sleeping species do when asleep. Humans and other species typically slept at night, and it was considered a necessity for proper functioning and personal performance. Lack of sleep would induce less effective performance and a bedraggled appearance in Humans, although other species might manifest a lack of sleep differently.

REM sleep was a stage of sleep necessary to most beings. If a person did not get the acquired amount, there could be repercussions, ranging from depression, exhaustion and hallucinations all the way to a possible psychotic break.

Droids could, in a manner of speaking, also sleep when they entered a powered-down state from time to time.

Reportedly, Darth Sidious killed his Master Darth Plagueis while the latter was sleeping.

Sleeping locations
Humans and other bipedal species usually slept on beds or bunks, though this was not always true, especially for sentients far from buildings or ships. Many ships, including the Millennium Falcon, were equipped with cabins or bunks for the purpose of sleeping. On planets, hotels were businesses designed to provide a place to sleep and stay the night for travelers. A common principle among military men was to sleep whenever one could wherever one could, a principle practiced by Leia Organa when she was a prisoner in Xizor's castle on Coruscant. Jaina Solo, during her tour of duty in the Battle of Borleias, sought out her parents' quarters and slept in their bed as it smelled like and reminded her of them, providing a more restful, relaxing environment for her to sleep.

Dreams
"I don't sleep well anymore."

- Anakin Skywalker admitting his troubling visions to Obi-Wan Kenobi

Some species experienced dreams while they slept. Jedi sometimes had visions of past, present, or future events while they slept. Anakin Skywalker had nightmarish visions of first his mother and later Padmé Amidala dying and in pain that prevented him from sleeping well. Disturbances in the Force could also cause Force-sensitives to awaken prematurely. While traveling in his personal starfighter to his lair on the third moon of Vassek, General Grievous dreamed of his past as a Kaleesh warlord and the glory of victories he'd won against his foes.

Attire
Among some cultures, depending on economic advantage and circumstances, people wore specialized attire for sleeping, as opposed to their everyday attire. Padmé Amidala, for example, wore one of several nightgowns when she was preparing for bed or when she slept. As a Jedi, Anakin Skywalker slept without a shirt or tunic, which was different from his typical daily Jedi robes. Corran Horn undressed completely to sleep when he first joined Rogue Squadron. Likewise, Aayla Secura usually slept without clothing save for an ornate red-and-gold floral robe that was opened wide. Most beings also used blankets or sleep sacks while sleeping and slept on a sleeper.

Non-canon appearances

 * Jedi Academy: Return of the Padawan
 * Goodnight Darth Vader