The National Sleep Foundation has revised its list of sleep duration recommendations.
According to their list, newborns (between 0-3 months) should get between 14-17 hours of sleep.
Infants (between 4 and 11 months) should be getting around 12 to 15 hours of sleep and toddlers (between 1 and 2 years) should be getting between 11 and 14 hours of sleep.
Pre-school age children (between 3 and 5 years) should be getting 10 to 13 hours and school age children (between 6 and 13 years) should get between 9 and 11 hours.
Teens (between 14 and 17 years) should be getting anywhere from 8 to 10 hours.
The numbers don't change much between young adults and adults (between 18 and 64 years) with 7 to 9 hours recommended.
Older adults (65 and older) should try for between 7 and 8 hours.
MORE INFO: http://sleepfoundation.org/