Expand / Collapse all hierarchy in Outliner How do I twirl down everything in a hierarchy in the Outliner? For example, on armatures it's sometimes tiresome having to click on the twirl down-arrow on every single bone if you want an overview of the armature in the Outliner. Is there a quicker way to do this?



Starting point.



This is what I would like to achieve without having to manually click on the twirl down-arrow on every single bone.

Please note: This is just an example armature and maybe not the best example. Sometimes there's armatures with over 100 bones, and I'm more specially talking about those cases where it actually gets very tiresome twirling down everything.
Simply click on expand arrow with Shift key.
It will expand/collapse everything under it. So if you need ...


expand all (under collection) - click on Collection
expand only specific bone chain - click on Armature


Example with and without Shift key:



Or use "+" / "-" key (with cursor in Outliner Editor) to open / close one level. 

More details in Blender Manual.