Whatever works, Dennis. I am lucky, I guess, in that coming originally from a classical background, the number of times I play a piece doesn't really have any effect on me. I mean, can you imagine how many times the Berlin Philharmonic has played Beethoven's Ninth, or Fifth?! I doubt you will EVER see them groan or roll their eyes or communicate anything other than reverence for the music and delight to be able to play it for their audience.
Same here. Margaritaville? No problem. It's a tune, no better or worse than any other. I tend to be simply happy if I'm playing..!
I certainly don't have anywhere NEAR the repertoire that you have on call, but what I do have doesn't require a chart. Swings and roundabouts, I suppose. My main way of increasing what I play in public is mostly to play a LOT with other people. I still prefer to work in more of the sideman or accompanist role. My voice is OK enough to do solos, but there are so many others FAR better than me! So, in the end, I end up not only having to learn MY repertoire, but that of many other people too. So I guess (I've never really bothered to count) it's reasonably up there.
But that sounds like a great act you have got going there, Dennis. I wish I could make it to Oz one day and come see it.
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An arranger is just a tool. What matters is what you build with it..!