Exactly. The pacing of a particular musical piece might not exactly match up with the timing and dialogue of a scene I write, but it may set the tone for it. I also sometimes select a track out of my collection to serve as a sort of auditory "trailer" for the entire story, or as a theme song for a character. I love Kevin MacLeod at Incompetech for literally giving away a great and eclectic selection of music from all genres. Many pieces sound just as professional and stirring as anything I could get from an album. I think half of my iTunes library is made up of his stuff, lol.