Duplicate objects in InDesign's Control panel.
Option-dragging is a shortcut to duplicate objects in most modern design applications. But in InDesign, duplicating with the Option key goes much deeper.
In InDesign, you can also hold down the Option key when making some Control panel adjustment to make a duplicate of your selected item. For example, if you make change to the location values and then hold down the Option key when typing Enter, a duplicate of your object will appear in the new location.
Windows Users: Use the Alt key for the same result.
Add InDesign's ability to perform basic math operations, and you have an great shortcut for quickly and precisely duplicating objects. (Read "Let your design apps do the math for you" back in QuickTips #24)
Source: This tip comes from the August 2007 issue of Design Tools Monthly. Seattle creative teams with a CreativeTechs support plan receive a complimentary subscription to Design Tools Monthly in their monthly care package.