In simple terms, DHCP determines if your IP is static or dynamic and the length of time an IP address is assigned. Dynamic Host Configuration Protocol is controlled by a DHCP server. Your router can be a DHCP server...and if you're on a home network, it most likely serves this purpose.
Researchers report that the average adolescent needs eight and a half to nine and a half hours of sleep each night. But in a poll taken in 2006 by the National Sleep Foundation, less than 20 percent reported getting that much rest on school nights.
It depends on your age and activity level as well as your health and lifestyle habits. No one really needs to be sleeping more than 9 hours a night. It is important to find the proper balance of sleep because studies show that people who sleep 8 hours or more, or less than 6.5 hours, don't live as long as those who get between 6.5 and 7.5 a night.