Sheet music
If there is a choir or solo singers their part is written near the bottom, above the strings.  Except for vocal parts, bar lines will usually join up the staves of each family.  Not joining them for vocal parts allows greater flexibility for placement of lyrics.  Joining bar lines makes it easier to find the instruments than if they had been drawn all the way down the page. An experienced conductor knows score order well enough to examine a score and very quickly see which instrument plays a given part, even if the instrument names are not there. Below is an example of score order for a standard orchestral score as it would be listed alongside the staves.