You can tell when a piece will end within seconds of the actual event by sight and this can be very important to the programmer who plays so much new stuff that intimate familiarity is not always possible. You can also skip through an entirely unfamiliar record on the spot if you have a mind to play something just fresh in. You do this by finding the general place visually first, and only then do you listen for the exact spot. The pieces are virtually invisible. Since cassettes are inherently so non-visual, the printed word can go a long way in aiding programmers willing to play them.
Description is important.
Just as important as providing this information is ensuring that it stays with the cassette. Four-second gaps of silence is a minimum safe bet. To maximize exposure of the music on a tape, we strongly recommend that the recordings fill the tape on both sides from end to end as nearly as possible. Some musicians have opted to present several short tapes for airplay with a single piece recorded on both sides, or a selection of a few songs, rather than a full length with several pieces recorded on it. This solves most cueing problems.