I've recently got hold of a Plantronics Voyager Legend bluetooth headset so that I can wander round the home office a little more when on my (never ending) conference calls.
It all seems to work nicely, except that Skype doesn't really "see" it properly so I need to manually switch Audio sources at the OS level when I want to use it with Skype. This initially felt like a real faff; open System Preferences, open Sound, set the Output and then set the Input.
This morning I was playing around and noticed that if I hold the Option key down while clicking the Sound option in the menu bar I see the different sound sources and can change them without having to go via Settings.
It's nice to find new tricks in an OS I've been using for decade.