Well, at least, playing Cirque material always leaves you a bit of wiggle room, as you have to play along what's happening on stage, and due to the human factor, that can potentially change all the time - so, yeah, they're the same songs, but they more or less keep you on your toes every show, stretching here and cutting there.
Nevertheless, it's pretty impressing that someone wouldn't miss a single day in 21 year - no sick day, no bereavement day, no FMLA, no nothing.
At my last job, I know many people who called in sick every Super Bowl...