[Al Skierkiewicz]

Answering the original question...It depends.
I prefer to use #10 for all drive motor wiring. In general, we will mount the controllers for the drives near enough to the motors to use the supplied motor wiring directly to speed controller. We use #10 for any motor with higher current, Chalupa large and small, Fisher Price, etc. #18 power wiring for all Spikes not feeding motors, and larger if feeding a motor.
We will submit to using the minimum guage when weight is an issue, i.e. at the end of the arm last year or when the robot is really overweight and the lower guage won't affect performance. Sensors use #24 or #22 depending on where they are located and what they are used for. Wheel speed sensors that we have used in the past for crab drive, might get a #22 to connect to the drive module and then transition to a #24. Pots and switches get #24, since we use PWM bulk cable for wiring those devices. And of course, short pieces of #6 to connect the fuse panels, main breaker, battery and the Rockwell block.