I want to run a routine on each sheet in the workbook. As
the numberf of sheets may change, I would prefer not to
refer to them by name.

Can anyone advise on the With/End With or For / Next code
into which I can put my routine? So far I have got

Sub UpdateFalseNew()
Dim wrkBook As Workbook
Dim wrkSht As Sheets

wrkBook = ThisWorkbook

For Each wrkSht In wrkBook
wrkSht.Select
setupdatefalse
Next wrkSht

End Sub