Illustrator's Snap to Units tab feature makes it easy to set precise tabs
Adobe Illustrator’s Tab panel offers a little-known feature that helps you set tabs at specific measurement units on the ruler called Snap to Unit. It’s particularly helpful if you want to set several tabs at exactly the same increments.
To use it, simply select your tabbed text and open the Tabs panel (Command + Shift + T). If the Tab panel isn’t located right above your text, simply click the little magnet icon in the panel to line it up. Now choose Snap to Unit under the flyout menu in the Tab panel. Now when you click in the ruler to set your tabs, the tab stops will automatically jump to the nearest tick mark on the ruler as you drag the tab stops around.
If you’re like me and you don’t want to go through the hassle of using the menu, you can simply hold the Shift key down while dragging your tab stops around on the ruler.