I have the code below, which runs when I deactivate a worksheet, but I
only want it to run the first time the worksheet is deactivated (in
any one session of using the workbook). If it’s activated and then
deactivated again (in any one session of using the workbook), I want
it not to run.

Private Sub Worksheet_Deactivate()
Counterstation = Workbooks("h...).Range("S38").Value
Select Case Counterstation
Case "CAM1": Do A
Case "CAM2": Do B
Case "CAM3": Do C
Case "CAM4": Do D
Case "HEL1": Do E
Case "HEL2": Do F
End Select
End Sub


I’ve tried this:

Private Sub Worksheet_Deactivate()
If x 0 Then Exit Sub
Counterstation = Workbooks("h...).Range("S38").Value
Select Case Counterstation
Case "CAM1": Do A
Case "CAM2": Do B
Case "CAM3": Do C
Case "CAM4": Do D
Case "HEL1": Do E
Case "HEL2": Do F
End Select
x=1
End Sub

(with x set as 0 in another piece of code which runs 'on open'), but
it won’t work.