Either way, as a DJ, your familiarity level is expected to be much, much higher than the average listener that is only familiar with.......(shall I say it?) ......300 or so songs.
The average listener is going to be familiar with thousands of songs. That includes the music of the 6 or 7 radio stations they listen to, songs they used to like but do not care much for now, songs they never liked, songs their parents played and many more.