Not if you're using lilypond-book. If you don't use \book, then you
can't use \pageBreak in your scores. There used to be a bug (in Aug)
wherein the horizontal alignment of some systems was also messed up
without \book; I'm not certain if that's still around.
That's a rather special issue and should be described in the
lilypond-book
manual. I still find the information about \book in the main manual
very
misleading, both in "8.1.4 Text markup", "10.1.12 Multiple movements"
and "5.8 File structure". If you agree, I can try to reformulate it.