I have two types of podcasts: those I listen to when doing work that is pretty mindless so I can focus on the podcast, and those that are entertaining but not important enough that it matters if I miss something while reading directions or thinking through next steps on my project, etc.

Come to think of it, I have one other category, actually, which are podcasts that are interesting but get a big backlog because I'm not that excited about them. I use those to fall asleep.