I will play devil's advocate and put in another thought or two.

Whereas, one could conceivably be a 10 instead of an 8 by sticking to one keyboard, look at the fun you missed along the way. It isn't just the destination, but, the journey.

I remember piano lessons as a child, where I would work on one piece until the teacher was satisfied. After a while I developed homicidal tendencies.

Don't forget that most of us reached the point of acceptability long ago, as far has handling an arranger is concerned.

Let us not forget about singing and entertaining, which, I think, is of equal importance.

Have fun, life is short.