I remember reading somewhere that too many FixedUpdates could lower performance. I wonder, does that also include separate scripts with different FixedUpdates, or just the set number of FixedUpdates-per-second?
'cause I would find it rather bothersome to have a script that cycles through all my rigidbodies just to update them all within a single FixedUpdate, just for the sake of improving performance. But at the same time, I want to make sure I've got it right from the beginning.
It is every FixedUpdate in your entire scene.
It should not matter though unless you are already pressed for a better frame rate. You would need a lot of Updates/FixedUpdates to really see a noticeable slow down.
But at the same time, I want to make sure I've got it right from the beginning.
For this specific optimization, I would not recommend doing it from the beginning unless you know that you will be forced to do it later, because it will make your code far more difficult to read and/or correct later, and unnecessary optimizing doesn't hurt, it just takes time, and time is valuable.