Harness the power of Symbols, by nesting them.
To create a nested Symbol, place an instance layer inside any other Symbol’s master Artboard. Any updates you make to the Symbol’s master will see the changes propagate throughout your design no matter if they’re inside another Symbol or not. As well as placing an instance into a master, and inserting via the toolbar item, you can also select multiple instances of different Symbols and press Create Symbol in the toolbar.
There’s no limit to how deep you can nest Symbols, but please note a Symbol cannot contain an instance of itself.
As mentioned in the Symbol Overrides chapter, nested Symbols can also be overridden, along with other properties in a Symbol’s instance.
Overriding a nested Symbol will allow you to swap out any Symbols contained in an instance—with any other Symbol that is the same size as that Symbol’s master, or instance. Say you had a Symbol of a toolbar that contains a Symbol of an icon. With the overrides, you could swap out the icon Symbol, with a Symbol of another icon—or nothing at all. These nested overrides mean that you can have fewer Symbols that are similar, and have more power and control over individual instances.
If you are using a nested Symbol in your document, and you don’t want to allow it to be overridden, just lock that layer from the Layer List or shortcut menu.