It's too easy not to run a cable from the - side of the battery to a ground block and branch off of that...When a electical problem pops up I know it's not a bad/loose ground, I can see everyone of them and they are all labeled.
IMO electical gremlins are the hardest to chase down so I like to keep it easy. Here's my finished panel. Fan and fuel pump relays are close to the source but still ground back to the battery.
