Pad vs Gain?

[Lazyfishstix]

This is probably a newbie question, but what exactly is the difference between engaging the pad of a mic/preamp and just lowering the gain? Are there situations where it's better to use one versus the other?

 

[bouldersoundguy]

When you set the gain to minimum and the signal is still too hot you can use the pad to give yourself more headroom. Typically it's good for line signals going into a mic pre and for micing loud stuff.