...if you're using an internal NTP server, by using a DNS A record like time.domain.com which points to your current NTP server. That way if you have to move the NTP service to another server you only have to update one entry in DNS to get your servers to update from the new server and you don't have to update every ESX host every time.

Could be a huge time saver if you have a bigger infrastructure. I have only got six ESXi boxes and I know this has saved me about half an hours work.