Checklist for Audio glitches/cracks/pops

[rdej47]

I'm not sure if this has been posted before but I thought it would be great if someone could post a sort of checklist of things to look for or to do if your audio is popping/cracking.

example:
1) Did you restart your computer (was your soundcard plugged in during restart?)

I feel like I'm just guessing at what to do when my audio starts popping and cracking.

[sine143]

Is one of your outputs set to SPDIF