Oh it works OK. The one time I did it was with an inherited document of over 400 pages. Although I did speed it up with a custom search routine for the phrase/word(s) I was particularly interested in. And yes, certainly content that may come in from other sources can be an issue. I think we can drop ths thread, as I just wanted to make the point (a bugbear of mine I admit), that in general, it is good document design to anticipate needs.
For example, whenever I make a new section break for a chapter, I always make three blank pages and set the header/footer for them immediately. I then delete the empty pages. The header/footer information for those pages remains, stored in the section break. That way if the text does in fact expand beyond one page the header/footer will automatically be filled in correctly.
Man, I gotta shut up. Sorry.
Gerry