I was in a meeting a few weeks ago where there was an argument over whether to use “New” or “Add” as a label for a command. The truth is, they’re different and not interchangeable at all. The simplest way I can explain this is by showing this example:

A window with both "New" and "Add" commands

This is an example of a design that actually can use both New and Add. It’s not that common to have both, but in this situation you can see how the two commands are different:

• Add Person will bring up a list of people that the software already knows about, and you can choose from that list to add people to this group (this would be a Person Chooser).
• New Person will bring up the “New Person” window and allow the user to enter all the data on a Person who is completely new to the software.

So I use New when you’re creating a new object in the software – something it didn’t previously know about. The New command typically brings up some sort of form, which the user needs to fill in.

I use Add when we’ll be grabbing an object from somewhere else and using it. This command typically brings up a chooser of some kind.

Enjoy!