There are different kinds of score that are quite common. For example, a close score , also called short score or condensed score , is a score that has two or more instrumental or vocal parts on each staff. The two-stave format is a commonly used short score type, and looks very much like a piano score. The stem direction seems to break the rule that notes above the middle line must point their stem downward, and notes below the middle line must point their stem upward. It is much more common for voices to perform from a score like this rather than instruments.
Instrumentalists prefer to see simply their own part on the page.
It is possible to have more than two staves in a short or close score. Sometimes composers will use multiple staves in this fashion, but will use the upper staves for the high notes and the lower staves for the low notes, then indicate with small lettering which instruments play which notes. The main advantage is that you are able to see the notes of a medium-sized orchestra at a glance. As you get better at recognizing chords, you can perceive the general tonality of the piece quickly using this type of score. The main disadvantage in using close score for orchestra is that it becomes rather difficult to narrow down which instrument is playing which notes.