I'm not so sure I've ever tested the meter I'm currently using (which I've had for several years!). The only time I remember going out and actually BUYING control solution was when I had completely lost faith in my old BD ParadigmLink meter (before they discontinued it and NovaMax resuscitated it) and needed to check if it still worked right. (I forget if it did or not).
But the mfr says to control-test every vial; that's one out of every 25 strips wasted. It's not worth the time or money to me.