Sub Check_Headers_And_Footers()
Dim i As Long
    For i = 1 To ActiveWorkbook.Sheets.Count
        With Sheets(i).PageSetup
            If .LeftHeader <> "Good Header" Then .LeftHeader = "Good Header"
            If .LeftFooter <> "Good Footer" Then .LeftFooter = "Good Footer"
        End With
    Next i
End Sub