Some of the things that you do in Illustrator remain “sticky” until you quit the application. For example, if you create a rectangle that’s 1 x 2 inches, the next time that you click with the Rectangle tool, the values are automatically set to 1 x 2 inches. All the dialog boxes in Illustrator remember what you did last during your current Illustrator session. (But don’t worry; they won’t tell a soul.)
Between sessions, the entries in the Preferences dialog box and the positions of the palettes are all that remain constant. Oh, well. At least something does.