I'm also used to listen to Columbo episodes in MP3 with my cellphone.
I can listen to them when I'm outside travelling by bus, or putting an episode on the laptop and leaving it repeat itself over and over, and during the night because I have nightmares relatively often and I try to relax with earphones while laying in bed in the darkness of my sleepingroom.

I was used to listen to "ashes to ashes" and "murder under glass", but more recently, it was "old fashioned murder" and "make me a perfect murder".

It's actually true that the dialogs tell almost everything and give the impression that the pictures are not absolutely necessary to understand the story. As I told somewhere else in the forum, Columbo is treated like a tale, which tells us, explain and describe us something, and give only a tiny place to action, which I appreciate...

I most often listen to "Make me a perfect murder". The scene early in the episode at the beach house is very pleasant to listen to. The sound of the surf and the birds, and the immortal line, "I can't give you the West Coast, babe".

Yeah, you're right. They are very soothing and comforting. Sometimes an episode even reminds me when i watched it on the Sunday night mystery movie when i was a kid in the 70's.

Oh my gosh! I thought I was the only one that did this! I have episodes on my tablet and almost ever night I watch Columbo episodes!! I don;t listen to them but actually watch them while I'm in bed!

I've done it with a lot of things, but seldom Columbos, I think. But there's at least one exception. I always liked those CBS Late Movie reruns (in spite of all the editing), and because of having insomnia I usually made it to the end and much later. The exception I can always think of is REQUIEM FOR A FALLING STAR. I started falling asleep right after Nora heard the news in the restaurant. (Since I'd never seen it before that I can think of, I thought her surprise - that it happened to Jean instead of Jerry - was for real.)