Cell Color changes On Input even if new input matches default...

I have a Macro Button which sets a Range of Cells to this default:
(example)
Sub SetDefaultCells()
Range("B10").Value = "8:30 AM"
Range("B10").Interior.Color = vbYellow
End Sub

How can I place a code into this cell so that when the user changes the time
it changes the cell color? My problem is that the user may need to keep it at
8:30 AM, so can I change the cell color even if the user inputs the same data
if they key in the same data as the default? This is why I can not use
conditional formatting. I can't use onActive Cell either because when the
user hits Enter it will go to the next cell and if I use onClick the user may
not use the click function.

Any help is greatly appreciated. Thanks!