When listening, licensing clients are often required to make quick judgement calls. By setting a cue you can ensure that they are basing their decision on the part of your submission that best matches their needs.
Setting a cue can be most effective when submitting a full song to an advertising opportunity. Agencies are often looking for a short, precise piece of music to enhance their promotion, as ads range from 30 to 60 seconds in length. If the relevant part of your submission is a couple of minutes into your track, it is a good idea to have the music licensing client start closer to the spot that has the right emotion, build, etc. that they are looking for.
It is important to note that cues are not always necessary and it can be more advantageous to have the client listen and experience the full version of the song. This can apply to Film and TV opportunities where your submission in its entirety captures the criteria and you want to avoid over guiding the client.
As with most things there is no set rule and you will have to rely on your best judgment in determining whether it is beneficial for you to set a cue. If you have any questions about setting cues please feel free to contact us at firstname.lastname@example.org.