Is it necessary to resend the frames if nothing changed?

[mrx23]

Hello!

Could you tell me that is it necessary to resend that frame which values didn't change (stick position remained the same).
So there will be no activity on the serial port if the sticks are not moved (not even sync bytes).
How will the simulation softwares tolerate this (like FMS)?

And why is that the stick positions only can vary between 0-254 and not between 0-255?

Thank you!