Thanks, NZEOD.
Let me clarify:
This is what I have, 3x servos, normal leds, blinking leds, and 1x neopixel.
The leds have resistors for 9-12v.
All will take the input power from the 5v Arduino board.
The question is, can i combine all the ground wires for all the above, or should i separate any ground wires?