The value will stay constant if you put it in a mod and this mod is active when you load your saves. If you changed it via a console command:
set MQ106TurnOffRandomDragons to x
x being 0 or 1, only your current save will be affected.
If you install a mod that turns off dragons it will effect all your characters as it is a game file change.
However if you make a change in the console command, it only effects THAT character and not any of your others.