Why did I read this thread! 
We have 7 phones in various rooms, all telling the time, 2 art deco clocks, 2 radio clock alarms (in different bedrooms) 2 electronic bedside clocks (in different rooms) 3 CD players, the cooker, the microwave, a kitchen wall clock, a modern cuckoo clock and a grandfather clock (which is actually my grandmother's grandmother clock)
Apart from the phones, I doubt any of them agree. One art deco (chiming) clock loses time as it needs winding but the 'grandfather' clock gains it. The 'grandfather' clock is in the hall where the business phone is kept and has Westminster chimes. I swear it knows when the phone rings as it always chimes while I am taking down details and, usually, it is the full hour, so 16 chimes, plus the actual hour - so at noon it chimes 28 times.