When extracting parts, assign cues sparingly to a pro or semi-pro level work. Best cues are after:
a. long stretches of over 30 bars
b. extended passages of metric complexity, and/or changes of meter and tempo
c. a very long cadenza.
It’s not necessary to pepper your score with cues after every tacet. Pro orchestra players are used to counting, and will make their own marks as needed. In fact, they will tend to ignore or become impatient with too many cues, as if you think that they’re high school band musicians. However, be aware that certain players may require more cues, as they traditionally have limited parts and do a lot of waiting and counting. These would be percussionists/timpanists, bass trombonists, tuba players, and so on.
In the example below, the bassoon I part from my harp concerto (which I extracted last night), I’ve inserted a cue after a very long passage, which illustrates both the bass trombone and clarinet lines coming right before the entrance. Note that I’ve kept bar rests running beneath the cue, indicating the player’s continuing tacet. Also, the cue is written in mini-notes. I’ll have more to say about cues tomorrow.