Ammeter Battery overcharge

I cry a little when people take out their ammeters.
It's like taking out your center inside rear view mirror, and relying on a digital readout to tell you how far the next car is behind you.

Not nearly as much, or enough information.
You can have a reaalllly bad short for quite a while somewhere out in the body, and have a fire long before you notice a voltage sag especially while driving.
If that situation occurs with an ammeter, you will see a big discharge and be able to take immediate shutdown action.
Happened to me on July 4th.
Was only a 10 min. delay, not a ruined day.