Not sure if this works for cells with functions but I found this code elsewhere for single cell entries and modified it for my use. If done properly, you do not need to worry about entering a function in a cell or the file changing the dates to that day's date every time it is opened.
- open Excel
- press "Alt+F11"
- Double-click on the worksheet that you want to apply the change to (listed on the left)
- copy/paste the code below
- adjust the Range(:) input to correspond to the column you will update
- adjust the Offset(0,_) input to correspond to the column where you would like the date displayed (in the version below I am making updates to column D and I want the date displayed in column F, hence the input entry of "2" for 2 columns over from column D)
- hit save
- repeat steps above if there are other worksheets in your workbook that need the same code
- you may have to change the number format of the column displaying the date to "General" and increase the column's width if it is displaying "####" after you make an updated entry
Copy/Paste Code below:
Private Sub Worksheet_Change(ByVal Target As Range)
If Intersect(Target, Range("D:D")) Is Nothing Then Exit Sub
Target.Offset(0, 2) = Date
End Sub
Good luck...