Efficient way to Hide all rows with a 0 in a column every time a cell value is changed

Hi Sky,

Here's a block "hide" that might work for you:

Private Sub Worksheet_Change(ByVal Target As Range)
Dim i As Long, j As Long
If Target.Address = "$A$1" Then
        Range("A2:A60").EntireRow.Hidden = True
        Select Case Target.Text
            Case "Red":         Range("A2:A20").EntireRow.Hidden = False
            Case "Green":       Range("A21:A40").EntireRow.Hidden = False
            Case "Bue":         Range("A41:A60").EntireRow.Hidden = False
            For i = 2 To Range("A" & Rows.Count).End(xlUp).Row
            If Range("A" & i) = 0 Then
            Do Until Range("A" & j + 1) <> 0: j = j + 1: Loop
            Range("A" & i & ":A" & j).EntireRow.Hidden = True
            End If: Next i
            
    End Select
    End If
End Sub