Yes, I record and no I've never asked for permission. I do not use the recordings for anything other than to remind myself of what happened in session. I used to dissociate badly and wouldn't remember much of my sessions. That's when I started recording. I've since found it helpful and have continued, even though I dissociate much less.

If I were to want to post or publish the recordings, I would certainly ask T's permission first. However, since I'm the only one that listens to them and I often delete them after a couple of days, I don't see the need to get permission.