while some music is arranged so that the pages end at places where the musician can spare one hand to turn them, this is not always possible. a page-turner is often needed by musicians who are playing difficult pieces and prefer not to play from memory. a page-turner needs to be able to understand the musician's signals and follow the music to know when to turn the page. page-turners are sometimes friends of the performer or members of the accompanying orchestra helping the musician. professional page-turners are usually freelance casual workers.