I recently totted up and listed titles in notes on my phone about 120 songs (and monologues) that I felt I could perform as opposed to "see if I remember." Mainly traditional songs, but a number of what is increasingly called acoustic roots.

Funny thing is, the next night at a club I help run, I played half a dozen songs and none were on the list.

Years of changing your set, not wishing to repeat too many and regular bookings where you should (but rarely did) make a note of what you played there last time means that the repertoire does increase somewhat.

Now.. of course, some you tend to be far happier with than others and places you go to regularly, its nice to get requests so you do repeat yourself, so a "regular" list for me is bout thirty songs at most.

In terms of song rate, I'm with Al. A folk club audience doesn't mind a bit of provenance waffle before the song and if you can slip in a knob gag or two, all the better.