My T manages his own schedule. For the first ~4 months, we determined the day and time of each session weekly. In the past ~2 months I have a slot for the same time and day every week. I was fine with both styles but asked the T to find a set time after a while so that we don't need to deal with that at the end of every session. I also ended up liking it better than scheduling all over the map. He is always responsive and flexible to re-schedule when something gets in the way.