Find and replace across all section headers in a long document

See the article "Using a macro to replace text where ever it appears in a document including Headers, Footers, Textboxes, etc.” at:

http://www.word.mvps.org/FAQs/MacrosVBA/FindReplaceAllWithVBA.htm

Using StoryRanges (as per the link) with Find/Replace in headers & footers is unreliable in multi-section documents. My preferred approach is along the lines of:

Sub Demo()
Application.ScreenUpdating = False
Dim Rng As Range, Sctn As Section, HdFt As HeaderFooter, Fnd As String, Rep As String
Fnd = "Find Text": Rep = "Replace Text"
With ActiveDocument
  For Each Rng In .StoryRanges
    Select Case Rng.StoryType
      Case wdPrimaryFooterStory, wdFirstPageFooterStory, wdEvenPagesFooterStory, _
        wdPrimaryHeaderStory, wdFirstPageHeaderStory, wdEvenPagesHeaderStory
      Case Else
        Call RngFndRep(Rng, Fnd, Rep)
    End Select
  Next
  For Each Sctn In .Sections
    For Each HdFt In Sctn.Headers
      With HdFt
        If .LinkToPrevious = False Then
          Call RngFndRep(HdFt.Range, Fnd, Rep)
        End If
      End With
    Next
    For Each HdFt In Sctn.Footers
      With HdFt
        If .LinkToPrevious = False Then
          Call RngFndRep(HdFt.Range, Fnd, Rep)
        End If
      End With
    Next
  Next
End With
Application.ScreenUpdating = True
End Sub

Sub RngFndRep(Rng As Range, Fnd As String, Rep As String)
    With Rng.Find
      .ClearFormatting
      .Replacement.ClearFormatting
      .Format = False
      .Forward = True
      .Wrap = wdFindContinue
      .Text = Fnd
      .Replacement.Text = Rep
      .MatchCase = True
      .MatchAllWordForms = False
      .MatchWholeWord = False
      .MatchWildcards = False
      .Execute Replace:=wdReplaceAll
    End With
End Sub

Yes, this worked for me, saving me hours of tedious labour.

Thanks for the follow-up!

By default, Word uses the Header style for text in headers. Just modify the font of that style. In the Apply Styles pane (Ctrl+Shift+S), type in Header and then click Modify. Specify the font you want and click OK.

All the replies to my query proved informative and helpful. Stephan's simple solution met my need, this time. Thanks, all!