alt Hacker NewsEh, if you only have a clock on only the microwave or oven then you lose access to the current time when you're cooking something or convert it over to timer mode. Having some redundancy isn't a bad thing in this instance.
Or simply have a dedicated clock in there and turn off the display on all of the appliances.
There should be two kinds of devices in my home: those allowed to connect to the Internet and keep their time up to date, and those that are not allowed to care what time it is. My microwave and my oven are in the latter category.