Use Global Colors
When working with color in your Illustrator documents, it’s almost always best to work with global swatches. A global swatch is a saved color found in the Swatches panel, and any artwork with the global swatch applied will update when the swatch color values are changed.
When you make a swatch using any number of methods, you can select Global under the Color Type option (see Figure 8). Now, if you look at the swatch in the Swatches panel, it will have a little white arrow in the corner, indicating that it is global.
Figure 8 Creating a global color