How to make sure my Mac isn't making a sound using its speakers?

I'm working in an open space. And I always spend a few minutes making sure the sound is coming out of the AirPods/Bose.

And sometimes the sound comes from the Mac speakers, making loud noise to all the open space. (Even when the Bluetooth indicator shows the AirPods are connected...)

So I want to make sure, that no matter what, sound isn't coming from the internal speakers, only from AirPods/Bose/other connected device.

• Select your Macs internal speakers as the output
• Turn the volume to 0

Now if for whatever reason output does not occur over your headphones your speakers will still be muted.