A: No—there are apps that you’ll want to appear wherever you happen to be at the moment. Say you assigned System Preferences to a desktop, but you’re on a different one when you open it from the Apple menu or the Dock. Not only do you move to its assigned desktop, you’ll have to move back to where you were when you’re done. And where were you? Desktop 3…or was it desktop 2?

Your often-used-but-only-for-minutes applications, such as Address Book, iCal, and Font Book are usually best left homeless.

Q: When I Control-click on an application in the Dock, I see the option to assign the app to All Desktops. Why would I want to do that? Isn’t that the same as assigning it to no desktop at all?

A: Assigning an application to All Desktops is different from assigning it to None. Without an assigned desktop, an app opens wherever you’re working at the time. Move from that desktop, and you leave the app behind; return to the desktop and it’s waiting there. When an app is assigned to All Desktops, it opens on the current desktop, but no matter what desktop you move to, it goes with you. This stalker-like behavior is very useful for certain utilities. You might, for instance, want your Twitterrific window always visible no matter how much you move around.

Q: Do I have to go into Mission Control just to move a window from one desktop to the next?