I’ve been using Ubuntu 18 for quite some time now. One thing that is frequently not working properly is the sound output switches. It happens from time to time that if I connect my Ubuntu laptop to a monitor, or a headset, the system will lose track of its desired sound output. I have to go into the sound settings and manually switch the output profile between HDMI and hifi (which I suppose is the default laptop sound output). A little bit tedious.