I don't have a problem with changing the clocks, except for one.
It's a small travel clock that runs from an AA battery.
The problem is that the buttons on top to set the alarm and time are so old they don't make contact anymore. You can't adjust the clock that way.
The only recourse is to remove the battery, and replace it.
The clock defaults to "1.00".
So each change of the clock, I have to have it in my hands at "1" (new time) and quickly remove and replace the battery...!