Very good info here, I myself have asked the same question, specially last years when I was shopping for a new radio since my old one has been with me for over 10 years without a single problem, so after doing some thinking on what I wanted to do as far as jets go, I came to the conclusion that I was going to be ok with 10 channels radio, so then I got me the Futaba 10CAP one step above the 9 CAP, I conceder what I was going to do with it, another thing to conceder is that some servos like the Hitec ones are programmable and that could eliminate the use of a channel by pairing two servos the same way.

So for now for me a 10 chls is more than enough,