In a network, it is extremely important that all devices that participate in it be in sync with one another.
By this I mean, their clocks should all be the same down to the second, heck, to a millisecond if you ask me; if they aren't, you could run into trouble. Just think about DC replication, DNS replication, intersite or intrasite replication, and the list does not stop there. And that's just Microsoft. The routers and switches that you are using must be in sync with one another as well, or updates will come in late or not at all. This in turn will hurt all your Microsoft devices as well.
Something else to think about is troubleshooting. You must have a timestamp when things go wrong, so you can have documentation as to when it all went bonkers, or if you are doing an update to your hardware or software, we should all be in sync so...
