Because of all the el cheapo quartz clocks in offices it is often that clocks show all different times in big offices.
The old master / slave clocks at least had all the clocks showing the correct time.
I use a Bürk pendulum master clock at home which drives about 30 slave clocks in all the rooms of my house ( Ok i admit, hobby out of control ). These keep time within 3 seconds per month, and automatic adjustment after a powercut.
Note: i live in a 5 bedroom house
People now rely more on cellphones, or quartz watches for timekeeping
