Save Grid Zero Point ?

It's only when you have a specific need that you notice it isn't there.  In this case I needed to demonstrate symmetry.  The bottles are pre-production and hand labeled, which means they tend to be slightly crooked and not aligned with each other.  So a centered zero point helps me nudge the labels into place, and vertical center of the bottle.  If the client wants the PSD file, then it's a nice touch to provide it with guides turned on, but the trick falls flat on its face if the grid zero reverts to the top left corner when they open it.

In actual fact, I did a double take when seeing the non centered grid zero, and had to open the other files before I could accept that the center was lost when reopening.  Like I said.  It's not until you need to use it, that you discover it is not there.