Combine Two Similar Private Subs

Absolutely. See here on where I got it from and it's purpose.

Okay sweet, thank you - I'm still trying to see how you combined the two, apparently it's not just an easy matter of copying and pasting in the right location.

And yes, I find it irritating as well! I still can't believe the fact that there's no way I'm not able to click once on a cell to check it, then click the same cell again to un-check it without having some other cell getting in the way, but oh well.

Technically, I guess so!

So if I decided to go with this less annoying code instead:

Option Explicit

Private Sub Worksheet_SelectionChange(ByVal Target As Range)
If Target.Cells.Count > 1 Then Exit Sub

    Select Case Target.Address
        Case "$A$14", "$G$14", "$L$14"
            If Target = "P" Then Target = "" Else Target = "P"
    End Select

End Sub

..how would that combine? I see you're adding tCell and rCell? Is there a standard way of combining formulas like these? I may have to do this to several more sheets in my workbook.

So if this..

Private Sub Worksheet_SelectionChange(ByVal Target As Range)
    With Range("X1")
        If .Value = Empty Then
            Application.EnableEvents = False
            .Select
            MsgBox "Please enter the number of pages required."
            Application.EnableEvents = True
        End If
    End With
End Sub

..plus this..

Option Explicit

Private Sub Worksheet_SelectionChange(ByVal Target As Range)
If Target.Count > 1 Then Exit Sub
    If Not Intersect(Target, Range("A14,G14,L14,Q14,U14,A16,A18")) Is Nothing Then
        If Target.Value = "P" Then
             Target.Value = ""
        Else
             Target.Value = "P"
        End If
    Range("G12").Select  ' or whatever cell you want selected after a click.
    End If

End Sub

..equals this:

Private Sub Worksheet_SelectionChange(ByVal Target As Range)
    Dim rCell As Range
    With Range(tCell)
        If .Value = Empty Then
            Application.EnableEvents = False
            .Select
            MsgBox "Please enter the number of pages required."
            Application.EnableEvents = True
        End If
    End With
    If Not Intersect(Target, Range("A14,G14,L14,Q14,U14,A16,A18")) Is Nothing Then
        For Each rCell In Intersect(Target, Range("A14,G14,L14,Q14,U14,A16,A18")).Cells
        If rCell.Value = "P" Then
             rCell.Value = ""
        Else
             rCell.Value = "P"
        End If
    Next rCell
    Range("G12").Select  ' or whatever cell you want selected after a click.
    End If
End Sub

..then would this..

Private Sub Worksheet_SelectionChange(ByVal Target As Range)
    With Range("X1")
        If .Value = Empty Then
            Application.EnableEvents = False
            .Select
            MsgBox "Please enter the number of pages required."
            Application.EnableEvents = True
        End If
    End With
End Sub

..plus this..

Option Explicit

Private Sub Worksheet_SelectionChange(ByVal Target As Range)
If Target.Cells.Count > 1 Then Exit Sub

    Select Case Target.Address
        Case "$A$14", "$G$14", "$L$14"
            If Target = "P" Then Target = "" Else Target = "P"
    End Select

End Sub

..equal.. this?

Private Sub Worksheet_SelectionChange(ByVal Target As Range)
    Dim rCell As Range
    With Range(tCell)
        If .Value = Empty Then
            Application.EnableEvents = False
            .Select
            MsgBox "Please enter the number of pages required."
            Application.EnableEvents = True
        End If
    End With
    Select Case Target.Address
        Case "$A$14", "$G$14", "$L$14"
            If Target = "P" Then Target = "" Else Target = "P"
    End Select
    End If
End Sub

Hmpf. Apparently not as I'm getting errors with it.

When I take that away, I get more errors.

If I do this:

Private Sub Worksheet_SelectionChange(ByVal Target As Range)
    Dim rCell As Range
    With Range(tCell)
        If .Value = Empty Then
            Application.EnableEvents = False
            .Select
            MsgBox "Please enter the number of pages required."
            Application.EnableEvents = True
        End If
    End With
    Select Case Target.Address
        Case "A$14","$G$14", "$L$14"
            If Target = "P" Then Target = "" Else Target = "P"
    End Select
End Sub

I get this error- Haha, and now it works, of course. Wow. There is still one issue, however. I don't know how difficult the fix would be, but by clicking any of the cells listed in the second part of the code (A14, G14, or L14) the first part of the code (which requires a page number to be entered before any other cell gets data entered) gets bypassed and the checkbox cell gets changed. The Message Box does appear, but after clicking OK, the checkbox cell that was clicked changes.

Is there something we can change to solve this?

Oh wow, that's fantastic! Thank you so much for all your help. Much appreciated!