Which To Use and Why?
Now that you know the facts about each of these interface elements, how do you decide which to use? The answer is simple: Use both.
Here's how I use them.
Dock. I set up the Dock as a "launch pad" for the applications and documents I use often. You already got a glimpse of how I use folders in the Dock. The Dock on my production computer (the one I use to write and do other work) is completely customized and bears little resemblance to the default Dock on my test mule (the computer on which I run software while writing a book or article about that software). The Dock is full of folders I can use to launch applications and documents quickly. It also has applications that I use often to open documentsfor example, Photoshop is on my Dock so I can open graphic files by dragging them onto that Photoshop icon. (Let's face it; Preview is extremely limited.) And, of course, my Dock is set to hide automatically, so I don't have to look at it while I'm working.
Sidebar. I use the Sidebar for folders in which I store documents. This plan makes perfect sense, given that Sidebar volumes and folders appear in Open and Save As dialog boxes. I can get to a document-storage location quickly by just clicking an icon in the Sidebarwhether I'm in the Finder, opening a document from within an application, or saving a document. By having my document folders listed in the Sidebar, I can also limit the number of new windows that appear when I open folders.