I've been doing twice weekly for about 5 months now. I sometimes come in with something planned to talk about, written on an index card or, very occasionally, e-mailed in advance. But what I think I like the most about twice a week is that I feel OK if one session wanders way off from what I had intended to talk about, because I still have the other session that week. Before, I would sometimes feel like, "Oh no, I wasted that session, and now I have to wait another week." But now, there's less urgency (maybe that's not the right word). I feel more OK taking time to really explore things in a session and go off in a different (often helpful and insightful) direction without that sense of panic. I also find it easier to continue a topic from the previous session, because it's not like a whole week of my life has gone by. With weekly, particularly with my ex-T (less so with current T, even when we were once a week), I'd get caught up in recapping what happened the past week, and maybe discussing that, which would eat up a lot of session, so there was less continuity from session to session and less time to do deeper work.