DHCP provides to the computer Ip address, subnet mask, and IP addresses for DNS. When a computer is added to the network, the DHCP server should be configured to accept the new computer. DHCP can't assign the same IP address to more computers in the network, if the rules are not set exactly the nwtwork will have serious problems. A dhcp server is the perfect option for wireless networks, you don't know who will connect to the network, but you can register MAC address of network adapters from the computers you want to be conected to the network.
Setting a network can take a lot of time, if you have a great number of computers on it, and if you don't have dhcp server, you should configure each computer from that network. With DHCP you will need only to configure the server, on the other computers you will need only to install drivers for network adapters ( if required ).
DHCP was first introduced by Microsoft in Windows NT version 3.5, in late 1994, now, more and more networks, especially internet service providers or networks with a large number of computers, use DHCP servers for dinamic alocation of IP addresses.
By: Apostol Lucian