Why Static IPs?

Okay, Here the scoop. We have 2 internal networks. net1 = gov. access. net2 =is local administration.(NOT gov.) I understand the need for static IPs on the Gov side, But why static IPson the other network(the last admin is MIA) and no real documentation. I would like to set the nongov side to have internet access, and only wireless is available. net2 runs peer-to-peer. My question is, could I change all systems to get IPs from DHCP? this would help to get the wireless up. oh net2 static ip is not 192.168.x.x or 10.x.x.x. Its confusing. I thought internal nets should be hidden from the internet. Any suggestions? thanks.