The Focus On Staves button on the Layout tab of Sibelius is an enormous time-saver, especially when working on a large score.
Basically, you select the staves you want to work on, or at least see, then press the Focus On Staves button, and all other staves disappear, leaving you to focus on just the staves you want to see.
The benefit is, though, that when you play your score, you hear every stave.
So if for example you are working on the string section of an orchestral score, but you also want to see the Flute line, because it is interacting with the Violin 1 part, you can focus on just those staves, but hear how they all fit in with the full score. If you want to only hear the visible staves, just select them all before you start playback.
Once you start using this feature, you will realise that it will save hours of selecting, deselecting etc.