Your code will look something like (*UNTESTED*):
Code:
Public Sub NewMonth(ThisDay As Date)
On Error GoTo Err_NewMonth
' Create a record for each day of the incoming date.
Dim MyRS As DAO.Recordset
Dim MyRecordCount As Integer
Dim WorkingDate As Date
Set MyRS = CurrentDb().OpenRecordset("tbl_aS_A1UnitInspection", dbOpenDynaset)
WorkingDate = DateSerial(Year(ThisDay), month(ThisDay), 1)
With MyRS
For MyRecordCount = 1 To Day(DateSerial(Year(ThisDay), month(ThisDay) + 1, 0))
.AddNew
MyRS!InspectionDate = WorkingDate
MyRS.Update
WorkingDate = WorkingDate + 1
Next
End With
Exit_NewMonth:
If Not MyRS Is Nothing Then
MyRS.Close
Set MyRS = Nothing
End If
Exit Sub
Err_NewMonth:
MsgBox Err & ": " & vbCrLf & Err.Description
Resume Exit_NewMonth
End Sub
...then all you need do is test if your *ThisDay* exists and if not then pass that date to this procedure.