Most adults feel refreshed with 7 to 9 hours of sleep, while children and teens usually need 9 to 12 hours depending on age.

Most adults need 7–9 hours of sleep per night to cycle through REM several times and wake with steady energy.

Most healthy adult males need 7–9 hours of sleep per night for steady energy and long-term health.

An 8-year-old usually needs 9–12 hours of sleep in each 24-hour day to stay healthy, learn well, and manage mood.

Most 9-month-old babies sleep 13–15 hours in 24 hours, split into 2–3 naps and around 11 hours at night.

Most 6-month-old babies need about 12 to 16 hours of total sleep in 24 hours, including 2 to 3 daytime naps.

Most women feel and function best with 7 to 9 hours of nightly sleep, adjusted for age, hormones, and health.

Most 5-month-old babies need about 12–16 hours of sleep in 24 hours, split between nighttime sleep and 3–4 daytime naps.

Healthy sleep for kids usually ranges from 9–12 hours per night, with younger children near 12 hours and teens near 8–10 hours.

Most older adults need about 7 to 8 hours of sleep each night to feel rested and protect long-term health.