3 deck mixing is the best for me...but u can still keep busy with 2..just all depends what level you take ur mixing to.
Get another copy of a trk ur playing and juggle them up..1 off,1 on...or a beat behind..sort of remix it up...use eq to make ur own drops,or just mix em quick..get as many trks played as u can,which will keep u busy more.

If ur just playing records..1 into the other..then yeah,ur gonna have spare time on ur hands in between trks and that can become boring.