Advancing to a new keyboard can produce a learning curve – But if you stay with the same make keyboard you lose about 75% of the relearning curve.
I traveled from a KN1000 (did not miss a model) to the KN7000. It was not a steep learning curve, one continued learning adding their knowledge to the next keyboard.

When I got the KN7000 I applied all that I learned for the previous models, a piece of cake. Not for self-edification, but I knew 95% of every feature on the KN7000.

I am trying to do the same thing with Yamaha – Psr2000 –Psr2100 – Psr3000 – Tyros 1 – Tyros 2 and now S900.

My thoughts, John C.