I don't think there has been less than 4, Because We Can, Water, What About Now, and Amen have been played pretty much every night (I think Amen was dropped once?) I think 4 is a good number, perhaps 5. They didn't really play a lot off The Circle either...I got 5 Circle songs at my first show on the tour (about 10 shows in) but only got 1 Circle song at the 2nd one (in 2011). I liked The Circle more than WAN.