I place great value on time. I am one of those people who makes sure that all the clocks in my home are kept right on time. When it comes time to change clocks due to the absurd practice of Daylight Savings Time, I go round the previous night and do so so that there is no danger of my doing something at the wrong time the following day. I am baffled by those who are not bothered that their clocks are wrong and find even more incomprehensible those who deliberately set their clocks fast in order to help them avoid being late for things. Having to constantly mentally adjust the time makes no sense to me.
I also like to be punctual, feeling that being on time for meetings shows respect for the value of other people’s time. Hence I have reminders for meetings and other events that alert me to get wherever I need to on time. I set these times and alerts on my calendar and reminders on my computer that these then get synced with my phone and my iPad so that when the time comes, all three of them sound alerts.
But I noticed that they would not all go off at the same time, and the time differences would change slightly, even though they were all supposedly automatically linked to the official time. Curious, I looked into why that might be so. The official US time signal is from the National Institute of Standards Technology and can be seen here. That webpage also shows you the time on the device you are using to access the site and it showed some interesting results. While my phone time differed from the NIST time by much less than a second, my computer time was off by more, sometimes of the order of seconds, and on one occasion was off by nearly two minutes.
It appears that this is because while they both supposedly should be synchronized with NIST time, the phone gets its signal from cell phone towers while the computer gets its time signal from Apple through the wi-fi system. I am guessing that the phone time is directly from NIST while the Apple time is subject to time shifts that can happen as signals travel through the internet. Interestingly, different computers connected to the same wi-fi connection can have slightly different time lags. That I have no explanation for.