<i>&gt;  ideally you would have each client syncing from three servers </i><p>For a small network (a home or small office network for instance) you likely have one incoming router anyway, so if that dies clock setting is the least of your worries until it comes back up, meaning setting the internal hosts by that one clock is as fine as anything else.<p>For a larger network you have redundant everything, including edge servers that can act as your multiple NTP sources for internal hosts rather than every internal host poking the public pool.