Recommended Sleep Duration
The amount of sleep an individual needs can vary from person to person but is largely dependent on age. On average, our bodies require less sleep as we get older. Check out this online sleep calculator from Sleep Foundation to get an idea of what time you should be falling asleep for your body to get the required sleep.
Resources
NHS Greater Glasgow and Clyde Information for parents: Sleep | NHS GGC
Sleep Foundation has lots of information on understanding sleep: Sleep Foundation | Better Sleep for a Better You