When there is drink involved sometimes it is good to have a list of songs to know where you are going.
With five in a band there is usually a bit of debate as to what song/tune is next. This can waste a lot of time.
We have about 200 songs/tunes and it can be good to have a few written down in front of yourself just as a reminder, sometimes the mind goes blank,
Seldom would we stick to the set list.