Considere this scenario, you migrate your Windows DHCP Server, it's all fine, but at the next day, you receive calls from a lot of users indicating that they cannot access the network. What's the issue? Your new DHCP Server is up the old was demoted, but clients cannot contact them, because your worstations have the old IP address. So, you run this easy and simple command, with administrative privileges over the workstations against you whole domain, and that's it.

psexec \\* ipconfig /renew

Don't forget to take in care some VM's or shadow servers that are maybe configured with any dinamic IP so you dont affect any other infrastructure service.